diff --git a/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/factory_test1.proto b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/factory_test1.proto
new file mode 100644
index 0000000..9f55e03
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/factory_test1.proto
@@ -0,0 +1,55 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: matthewtoia@google.com (Matt Toia)
+
+
+package google.protobuf.python.internal;
+
+
+enum Factory1Enum {
+  FACTORY_1_VALUE_0 = 0;
+  FACTORY_1_VALUE_1 = 1;
+}
+
+message Factory1Message {
+  optional Factory1Enum factory_1_enum = 1;
+  enum NestedFactory1Enum {
+    NESTED_FACTORY_1_VALUE_0 = 0;
+    NESTED_FACTORY_1_VALUE_1 = 1;
+  }
+  optional NestedFactory1Enum nested_factory_1_enum = 2;
+  message NestedFactory1Message {
+    optional string value = 1;
+  }
+  optional NestedFactory1Message nested_factory_1_message = 3;
+  optional int32 scalar_value = 4;
+  repeated string list_value = 5;
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/factory_test2.proto b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/factory_test2.proto
new file mode 100644
index 0000000..d3ce4d7
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/factory_test2.proto
@@ -0,0 +1,77 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: matthewtoia@google.com (Matt Toia)
+
+
+package google.protobuf.python.internal;
+
+import "google/protobuf/internal/factory_test1.proto";
+
+
+enum Factory2Enum {
+  FACTORY_2_VALUE_0 = 0;
+  FACTORY_2_VALUE_1 = 1;
+}
+
+message Factory2Message {
+  required int32 mandatory = 1;
+  optional Factory2Enum factory_2_enum = 2;
+  enum NestedFactory2Enum {
+    NESTED_FACTORY_2_VALUE_0 = 0;
+    NESTED_FACTORY_2_VALUE_1 = 1;
+  }
+  optional NestedFactory2Enum nested_factory_2_enum = 3;
+  message NestedFactory2Message {
+    optional string value = 1;
+  }
+  optional NestedFactory2Message nested_factory_2_message = 4;
+  optional Factory1Message factory_1_message = 5;
+  optional Factory1Enum factory_1_enum = 6;
+  optional Factory1Message.NestedFactory1Enum nested_factory_1_enum = 7;
+  optional Factory1Message.NestedFactory1Message nested_factory_1_message = 8;
+  optional Factory2Message circular_message = 9;
+  optional string scalar_value = 10;
+  repeated string list_value = 11;
+  repeated group Grouped = 12 {
+    optional string part_1 = 13;
+    optional string part_2 = 14;
+  }
+  optional LoopMessage loop = 15;
+  optional int32 int_with_default = 16 [default = 1776];
+  optional double double_with_default = 17 [default = 9.99];
+  optional string string_with_default = 18 [default = "hello world"];
+  optional bool bool_with_default = 19 [default = false];
+  optional Factory2Enum enum_with_default = 20 [default = FACTORY_2_VALUE_1];
+}
+
+message LoopMessage {
+  optional Factory2Message loop = 1;
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_extensions.proto b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_extensions.proto
new file mode 100644
index 0000000..e2d9701
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_extensions.proto
@@ -0,0 +1,58 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: robinson@google.com (Will Robinson)
+
+
+package google.protobuf.internal;
+
+
+message TopLevelMessage {
+  optional ExtendedMessage submessage = 1;
+}
+
+
+message ExtendedMessage {
+  extensions 1 to max;
+}
+
+
+message ForeignMessage {
+  optional int32 foreign_message_int = 1;
+}
+
+
+extend ExtendedMessage {
+  optional int32 optional_int_extension = 1;
+  optional ForeignMessage optional_message_extension = 2;
+
+  repeated int32 repeated_int_extension = 3;
+  repeated ForeignMessage repeated_message_extension = 4;
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_extensions_dynamic.proto b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_extensions_dynamic.proto
new file mode 100644
index 0000000..df98ac4
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_extensions_dynamic.proto
@@ -0,0 +1,49 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: jasonh@google.com (Jason Hsueh)
+//
+// This file is used to test a corner case in the CPP implementation where the
+// generated C++ type is available for the extendee, but the extension is
+// defined in a file whose C++ type is not in the binary.
+
+
+import "google/protobuf/internal/more_extensions.proto";
+
+package google.protobuf.internal;
+
+message DynamicMessageType {
+  optional int32 a = 1;
+}
+
+extend ExtendedMessage {
+  optional int32 dynamic_int32_extension = 100;
+  optional DynamicMessageType dynamic_message_extension = 101;
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_messages.proto b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_messages.proto
new file mode 100644
index 0000000..c701b44
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/more_messages.proto
@@ -0,0 +1,51 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: robinson@google.com (Will Robinson)
+
+
+package google.protobuf.internal;
+
+// A message where tag numbers are listed out of order, to allow us to test our
+// canonicalization of serialized output, which should always be in tag order.
+// We also mix in some extensions for extra fun.
+message OutOfOrderFields {
+  optional   sint32 optional_sint32   =  5;
+  extensions 4 to 4;
+  optional   uint32 optional_uint32   =  3;
+  extensions 2 to 2;
+  optional    int32 optional_int32    =  1;
+};
+
+
+extend OutOfOrderFields {
+  optional   uint64 optional_uint64   =  4;
+  optional    int64 optional_int64    =  2;
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/test_bad_identifiers.proto b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/test_bad_identifiers.proto
new file mode 100644
index 0000000..6a82299
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/python/google/protobuf/internal/test_bad_identifiers.proto
@@ -0,0 +1,52 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+
+
+package protobuf_unittest;
+
+option py_generic_services = true;
+
+message TestBadIdentifiers {
+  extensions 100 to max;
+}
+
+// Make sure these reasonable extension names don't conflict with internal
+// variables.
+extend TestBadIdentifiers {
+  optional string message = 100 [default="foo"];
+  optional string descriptor = 101 [default="bar"];
+  optional string reflection = 102 [default="baz"];
+  optional string service = 103 [default="qux"];
+}
+
+message AnotherMessage {}
+service AnotherService {}
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/descriptor.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/descriptor.proto
new file mode 100644
index 0000000..a785f79
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/descriptor.proto
@@ -0,0 +1,620 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// The messages in this file describe the definitions found in .proto files.
+// A valid .proto file can be translated directly to a FileDescriptorProto
+// without any other information (e.g. without reading its imports).
+
+
+
+package google.protobuf;
+option java_package = "com.google.protobuf";
+option java_outer_classname = "DescriptorProtos";
+
+// descriptor.proto must be optimized for speed because reflection-based
+// algorithms don't work during bootstrapping.
+option optimize_for = SPEED;
+
+// The protocol compiler can output a FileDescriptorSet containing the .proto
+// files it parses.
+message FileDescriptorSet {
+  repeated FileDescriptorProto file = 1;
+}
+
+// Describes a complete .proto file.
+message FileDescriptorProto {
+  optional string name = 1;       // file name, relative to root of source tree
+  optional string package = 2;    // e.g. "foo", "foo.bar", etc.
+
+  // Names of files imported by this file.
+  repeated string dependency = 3;
+  // Indexes of the public imported files in the dependency list above.
+  repeated int32 public_dependency = 10;
+  // Indexes of the weak imported files in the dependency list.
+  // For Google-internal migration only. Do not use.
+  repeated int32 weak_dependency = 11;
+
+  // All top-level definitions in this file.
+  repeated DescriptorProto message_type = 4;
+  repeated EnumDescriptorProto enum_type = 5;
+  repeated ServiceDescriptorProto service = 6;
+  repeated FieldDescriptorProto extension = 7;
+
+  optional FileOptions options = 8;
+
+  // This field contains optional information about the original source code.
+  // You may safely remove this entire field whithout harming runtime
+  // functionality of the descriptors -- the information is needed only by
+  // development tools.
+  optional SourceCodeInfo source_code_info = 9;
+}
+
+// Describes a message type.
+message DescriptorProto {
+  optional string name = 1;
+
+  repeated FieldDescriptorProto field = 2;
+  repeated FieldDescriptorProto extension = 6;
+
+  repeated DescriptorProto nested_type = 3;
+  repeated EnumDescriptorProto enum_type = 4;
+
+  message ExtensionRange {
+    optional int32 start = 1;
+    optional int32 end = 2;
+  }
+  repeated ExtensionRange extension_range = 5;
+
+  optional MessageOptions options = 7;
+}
+
+// Describes a field within a message.
+message FieldDescriptorProto {
+  enum Type {
+    // 0 is reserved for errors.
+    // Order is weird for historical reasons.
+    TYPE_DOUBLE         = 1;
+    TYPE_FLOAT          = 2;
+    // Not ZigZag encoded.  Negative numbers take 10 bytes.  Use TYPE_SINT64 if
+    // negative values are likely.
+    TYPE_INT64          = 3;
+    TYPE_UINT64         = 4;
+    // Not ZigZag encoded.  Negative numbers take 10 bytes.  Use TYPE_SINT32 if
+    // negative values are likely.
+    TYPE_INT32          = 5;
+    TYPE_FIXED64        = 6;
+    TYPE_FIXED32        = 7;
+    TYPE_BOOL           = 8;
+    TYPE_STRING         = 9;
+    TYPE_GROUP          = 10;  // Tag-delimited aggregate.
+    TYPE_MESSAGE        = 11;  // Length-delimited aggregate.
+
+    // New in version 2.
+    TYPE_BYTES          = 12;
+    TYPE_UINT32         = 13;
+    TYPE_ENUM           = 14;
+    TYPE_SFIXED32       = 15;
+    TYPE_SFIXED64       = 16;
+    TYPE_SINT32         = 17;  // Uses ZigZag encoding.
+    TYPE_SINT64         = 18;  // Uses ZigZag encoding.
+  };
+
+  enum Label {
+    // 0 is reserved for errors
+    LABEL_OPTIONAL      = 1;
+    LABEL_REQUIRED      = 2;
+    LABEL_REPEATED      = 3;
+    // TODO(sanjay): Should we add LABEL_MAP?
+  };
+
+  optional string name = 1;
+  optional int32 number = 3;
+  optional Label label = 4;
+
+  // If type_name is set, this need not be set.  If both this and type_name
+  // are set, this must be either TYPE_ENUM or TYPE_MESSAGE.
+  optional Type type = 5;
+
+  // For message and enum types, this is the name of the type.  If the name
+  // starts with a '.', it is fully-qualified.  Otherwise, C++-like scoping
+  // rules are used to find the type (i.e. first the nested types within this
+  // message are searched, then within the parent, on up to the root
+  // namespace).
+  optional string type_name = 6;
+
+  // For extensions, this is the name of the type being extended.  It is
+  // resolved in the same manner as type_name.
+  optional string extendee = 2;
+
+  // For numeric types, contains the original text representation of the value.
+  // For booleans, "true" or "false".
+  // For strings, contains the default text contents (not escaped in any way).
+  // For bytes, contains the C escaped value.  All bytes >= 128 are escaped.
+  // TODO(kenton):  Base-64 encode?
+  optional string default_value = 7;
+
+  optional FieldOptions options = 8;
+}
+
+// Describes an enum type.
+message EnumDescriptorProto {
+  optional string name = 1;
+
+  repeated EnumValueDescriptorProto value = 2;
+
+  optional EnumOptions options = 3;
+}
+
+// Describes a value within an enum.
+message EnumValueDescriptorProto {
+  optional string name = 1;
+  optional int32 number = 2;
+
+  optional EnumValueOptions options = 3;
+}
+
+// Describes a service.
+message ServiceDescriptorProto {
+  optional string name = 1;
+  repeated MethodDescriptorProto method = 2;
+
+  optional ServiceOptions options = 3;
+}
+
+// Describes a method of a service.
+message MethodDescriptorProto {
+  optional string name = 1;
+
+  // Input and output type names.  These are resolved in the same way as
+  // FieldDescriptorProto.type_name, but must refer to a message type.
+  optional string input_type = 2;
+  optional string output_type = 3;
+
+  optional MethodOptions options = 4;
+}
+
+
+// ===================================================================
+// Options
+
+// Each of the definitions above may have "options" attached.  These are
+// just annotations which may cause code to be generated slightly differently
+// or may contain hints for code that manipulates protocol messages.
+//
+// Clients may define custom options as extensions of the *Options messages.
+// These extensions may not yet be known at parsing time, so the parser cannot
+// store the values in them.  Instead it stores them in a field in the *Options
+// message called uninterpreted_option. This field must have the same name
+// across all *Options messages. We then use this field to populate the
+// extensions when we build a descriptor, at which point all protos have been
+// parsed and so all extensions are known.
+//
+// Extension numbers for custom options may be chosen as follows:
+// * For options which will only be used within a single application or
+//   organization, or for experimental options, use field numbers 50000
+//   through 99999.  It is up to you to ensure that you do not use the
+//   same number for multiple options.
+// * For options which will be published and used publicly by multiple
+//   independent entities, e-mail protobuf-global-extension-registry@google.com
+//   to reserve extension numbers. Simply provide your project name (e.g.
+//   Object-C plugin) and your porject website (if available) -- there's no need
+//   to explain how you intend to use them. Usually you only need one extension
+//   number. You can declare multiple options with only one extension number by
+//   putting them in a sub-message. See the Custom Options section of the docs
+//   for examples:
+//   http://code.google.com/apis/protocolbuffers/docs/proto.html#options
+//   If this turns out to be popular, a web service will be set up
+//   to automatically assign option numbers.
+
+
+message FileOptions {
+
+  // Sets the Java package where classes generated from this .proto will be
+  // placed.  By default, the proto package is used, but this is often
+  // inappropriate because proto packages do not normally start with backwards
+  // domain names.
+  optional string java_package = 1;
+
+
+  // If set, all the classes from the .proto file are wrapped in a single
+  // outer class with the given name.  This applies to both Proto1
+  // (equivalent to the old "--one_java_file" option) and Proto2 (where
+  // a .proto always translates to a single class, but you may want to
+  // explicitly choose the class name).
+  optional string java_outer_classname = 8;
+
+  // If set true, then the Java code generator will generate a separate .java
+  // file for each top-level message, enum, and service defined in the .proto
+  // file.  Thus, these types will *not* be nested inside the outer class
+  // named by java_outer_classname.  However, the outer class will still be
+  // generated to contain the file's getDescriptor() method as well as any
+  // top-level extensions defined in the file.
+  optional bool java_multiple_files = 10 [default=false];
+
+  // If set true, then the Java code generator will generate equals() and
+  // hashCode() methods for all messages defined in the .proto file. This is
+  // purely a speed optimization, as the AbstractMessage base class includes
+  // reflection-based implementations of these methods.
+  optional bool java_generate_equals_and_hash = 20 [default=false];
+
+  // Generated classes can be optimized for speed or code size.
+  enum OptimizeMode {
+    SPEED = 1;        // Generate complete code for parsing, serialization,
+                      // etc.
+    CODE_SIZE = 2;    // Use ReflectionOps to implement these methods.
+    LITE_RUNTIME = 3; // Generate code using MessageLite and the lite runtime.
+  }
+  optional OptimizeMode optimize_for = 9 [default=SPEED];
+
+  // Sets the Go package where structs generated from this .proto will be
+  // placed.  There is no default.
+  optional string go_package = 11;
+
+
+
+  // Should generic services be generated in each language?  "Generic" services
+  // are not specific to any particular RPC system.  They are generated by the
+  // main code generators in each language (without additional plugins).
+  // Generic services were the only kind of service generation supported by
+  // early versions of proto2.
+  //
+  // Generic services are now considered deprecated in favor of using plugins
+  // that generate code specific to your particular RPC system.  Therefore,
+  // these default to false.  Old code which depends on generic services should
+  // explicitly set them to true.
+  optional bool cc_generic_services = 16 [default=false];
+  optional bool java_generic_services = 17 [default=false];
+  optional bool py_generic_services = 18 [default=false];
+
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+message MessageOptions {
+  // Set true to use the old proto1 MessageSet wire format for extensions.
+  // This is provided for backwards-compatibility with the MessageSet wire
+  // format.  You should not use this for any other reason:  It's less
+  // efficient, has fewer features, and is more complicated.
+  //
+  // The message must be defined exactly as follows:
+  //   message Foo {
+  //     option message_set_wire_format = true;
+  //     extensions 4 to max;
+  //   }
+  // Note that the message cannot have any defined fields; MessageSets only
+  // have extensions.
+  //
+  // All extensions of your type must be singular messages; e.g. they cannot
+  // be int32s, enums, or repeated messages.
+  //
+  // Because this is an option, the above two restrictions are not enforced by
+  // the protocol compiler.
+  optional bool message_set_wire_format = 1 [default=false];
+
+  // Disables the generation of the standard "descriptor()" accessor, which can
+  // conflict with a field of the same name.  This is meant to make migration
+  // from proto1 easier; new code should avoid fields named "descriptor".
+  optional bool no_standard_descriptor_accessor = 2 [default=false];
+
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+message FieldOptions {
+  // The ctype option instructs the C++ code generator to use a different
+  // representation of the field than it normally would.  See the specific
+  // options below.  This option is not yet implemented in the open source
+  // release -- sorry, we'll try to include it in a future version!
+  optional CType ctype = 1 [default = STRING];
+  enum CType {
+    // Default mode.
+    STRING = 0;
+
+    CORD = 1;
+
+    STRING_PIECE = 2;
+  }
+  // The packed option can be enabled for repeated primitive fields to enable
+  // a more efficient representation on the wire. Rather than repeatedly
+  // writing the tag and type for each element, the entire array is encoded as
+  // a single length-delimited blob.
+  optional bool packed = 2;
+
+
+
+  // Should this field be parsed lazily?  Lazy applies only to message-type
+  // fields.  It means that when the outer message is initially parsed, the
+  // inner message's contents will not be parsed but instead stored in encoded
+  // form.  The inner message will actually be parsed when it is first accessed.
+  //
+  // This is only a hint.  Implementations are free to choose whether to use
+  // eager or lazy parsing regardless of the value of this option.  However,
+  // setting this option true suggests that the protocol author believes that
+  // using lazy parsing on this field is worth the additional bookkeeping
+  // overhead typically needed to implement it.
+  //
+  // This option does not affect the public interface of any generated code;
+  // all method signatures remain the same.  Furthermore, thread-safety of the
+  // interface is not affected by this option; const methods remain safe to
+  // call from multiple threads concurrently, while non-const methods continue
+  // to require exclusive access.
+  //
+  //
+  // Note that implementations may choose not to check required fields within
+  // a lazy sub-message.  That is, calling IsInitialized() on the outher message
+  // may return true even if the inner message has missing required fields.
+  // This is necessary because otherwise the inner message would have to be
+  // parsed in order to perform the check, defeating the purpose of lazy
+  // parsing.  An implementation which chooses not to check required fields
+  // must be consistent about it.  That is, for any particular sub-message, the
+  // implementation must either *always* check its required fields, or *never*
+  // check its required fields, regardless of whether or not the message has
+  // been parsed.
+  optional bool lazy = 5 [default=false];
+
+  // Is this field deprecated?
+  // Depending on the target platform, this can emit Deprecated annotations
+  // for accessors, or it will be completely ignored; in the very least, this
+  // is a formalization for deprecating fields.
+  optional bool deprecated = 3 [default=false];
+
+  // EXPERIMENTAL.  DO NOT USE.
+  // For "map" fields, the name of the field in the enclosed type that
+  // is the key for this map.  For example, suppose we have:
+  //   message Item {
+  //     required string name = 1;
+  //     required string value = 2;
+  //   }
+  //   message Config {
+  //     repeated Item items = 1 [experimental_map_key="name"];
+  //   }
+  // In this situation, the map key for Item will be set to "name".
+  // TODO: Fully-implement this, then remove the "experimental_" prefix.
+  optional string experimental_map_key = 9;
+
+  // For Google-internal migration only. Do not use.
+  optional bool weak = 10 [default=false];
+
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+message EnumOptions {
+
+  // Set this option to false to disallow mapping different tag names to a same
+  // value.
+  optional bool allow_alias = 2 [default=true];
+
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+message EnumValueOptions {
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+message ServiceOptions {
+
+  // Note:  Field numbers 1 through 32 are reserved for Google's internal RPC
+  //   framework.  We apologize for hoarding these numbers to ourselves, but
+  //   we were already using them long before we decided to release Protocol
+  //   Buffers.
+
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+message MethodOptions {
+
+  // Note:  Field numbers 1 through 32 are reserved for Google's internal RPC
+  //   framework.  We apologize for hoarding these numbers to ourselves, but
+  //   we were already using them long before we decided to release Protocol
+  //   Buffers.
+
+  // The parser stores options it doesn't recognize here. See above.
+  repeated UninterpretedOption uninterpreted_option = 999;
+
+  // Clients can define custom options in extensions of this message. See above.
+  extensions 1000 to max;
+}
+
+
+// A message representing a option the parser does not recognize. This only
+// appears in options protos created by the compiler::Parser class.
+// DescriptorPool resolves these when building Descriptor objects. Therefore,
+// options protos in descriptor objects (e.g. returned by Descriptor::options(),
+// or produced by Descriptor::CopyTo()) will never have UninterpretedOptions
+// in them.
+message UninterpretedOption {
+  // The name of the uninterpreted option.  Each string represents a segment in
+  // a dot-separated name.  is_extension is true iff a segment represents an
+  // extension (denoted with parentheses in options specs in .proto files).
+  // E.g.,{ ["foo", false], ["bar.baz", true], ["qux", false] } represents
+  // "foo.(bar.baz).qux".
+  message NamePart {
+    required string name_part = 1;
+    required bool is_extension = 2;
+  }
+  repeated NamePart name = 2;
+
+  // The value of the uninterpreted option, in whatever type the tokenizer
+  // identified it as during parsing. Exactly one of these should be set.
+  optional string identifier_value = 3;
+  optional uint64 positive_int_value = 4;
+  optional int64 negative_int_value = 5;
+  optional double double_value = 6;
+  optional bytes string_value = 7;
+  optional string aggregate_value = 8;
+}
+
+// ===================================================================
+// Optional source code info
+
+// Encapsulates information about the original source file from which a
+// FileDescriptorProto was generated.
+message SourceCodeInfo {
+  // A Location identifies a piece of source code in a .proto file which
+  // corresponds to a particular definition.  This information is intended
+  // to be useful to IDEs, code indexers, documentation generators, and similar
+  // tools.
+  //
+  // For example, say we have a file like:
+  //   message Foo {
+  //     optional string foo = 1;
+  //   }
+  // Let's look at just the field definition:
+  //   optional string foo = 1;
+  //   ^       ^^     ^^  ^  ^^^
+  //   a       bc     de  f  ghi
+  // We have the following locations:
+  //   span   path               represents
+  //   [a,i)  [ 4, 0, 2, 0 ]     The whole field definition.
+  //   [a,b)  [ 4, 0, 2, 0, 4 ]  The label (optional).
+  //   [c,d)  [ 4, 0, 2, 0, 5 ]  The type (string).
+  //   [e,f)  [ 4, 0, 2, 0, 1 ]  The name (foo).
+  //   [g,h)  [ 4, 0, 2, 0, 3 ]  The number (1).
+  //
+  // Notes:
+  // - A location may refer to a repeated field itself (i.e. not to any
+  //   particular index within it).  This is used whenever a set of elements are
+  //   logically enclosed in a single code segment.  For example, an entire
+  //   extend block (possibly containing multiple extension definitions) will
+  //   have an outer location whose path refers to the "extensions" repeated
+  //   field without an index.
+  // - Multiple locations may have the same path.  This happens when a single
+  //   logical declaration is spread out across multiple places.  The most
+  //   obvious example is the "extend" block again -- there may be multiple
+  //   extend blocks in the same scope, each of which will have the same path.
+  // - A location's span is not always a subset of its parent's span.  For
+  //   example, the "extendee" of an extension declaration appears at the
+  //   beginning of the "extend" block and is shared by all extensions within
+  //   the block.
+  // - Just because a location's span is a subset of some other location's span
+  //   does not mean that it is a descendent.  For example, a "group" defines
+  //   both a type and a field in a single declaration.  Thus, the locations
+  //   corresponding to the type and field and their components will overlap.
+  // - Code which tries to interpret locations should probably be designed to
+  //   ignore those that it doesn't understand, as more types of locations could
+  //   be recorded in the future.
+  repeated Location location = 1;
+  message Location {
+    // Identifies which part of the FileDescriptorProto was defined at this
+    // location.
+    //
+    // Each element is a field number or an index.  They form a path from
+    // the root FileDescriptorProto to the place where the definition.  For
+    // example, this path:
+    //   [ 4, 3, 2, 7, 1 ]
+    // refers to:
+    //   file.message_type(3)  // 4, 3
+    //       .field(7)         // 2, 7
+    //       .name()           // 1
+    // This is because FileDescriptorProto.message_type has field number 4:
+    //   repeated DescriptorProto message_type = 4;
+    // and DescriptorProto.field has field number 2:
+    //   repeated FieldDescriptorProto field = 2;
+    // and FieldDescriptorProto.name has field number 1:
+    //   optional string name = 1;
+    //
+    // Thus, the above path gives the location of a field name.  If we removed
+    // the last element:
+    //   [ 4, 3, 2, 7 ]
+    // this path refers to the whole field declaration (from the beginning
+    // of the label to the terminating semicolon).
+    repeated int32 path = 1 [packed=true];
+
+    // Always has exactly three or four elements: start line, start column,
+    // end line (optional, otherwise assumed same as start line), end column.
+    // These are packed into a single field for efficiency.  Note that line
+    // and column numbers are zero-based -- typically you will want to add
+    // 1 to each before displaying to a user.
+    repeated int32 span = 2 [packed=true];
+
+    // If this SourceCodeInfo represents a complete declaration, these are any
+    // comments appearing before and after the declaration which appear to be
+    // attached to the declaration.
+    //
+    // A series of line comments appearing on consecutive lines, with no other
+    // tokens appearing on those lines, will be treated as a single comment.
+    //
+    // Only the comment content is provided; comment markers (e.g. //) are
+    // stripped out.  For block comments, leading whitespace and an asterisk
+    // will be stripped from the beginning of each line other than the first.
+    // Newlines are included in the output.
+    //
+    // Examples:
+    //
+    //   optional int32 foo = 1;  // Comment attached to foo.
+    //   // Comment attached to bar.
+    //   optional int32 bar = 2;
+    //
+    //   optional string baz = 3;
+    //   // Comment attached to baz.
+    //   // Another line attached to baz.
+    //
+    //   // Comment attached to qux.
+    //   //
+    //   // Another line attached to qux.
+    //   optional double qux = 4;
+    //
+    //   optional string corge = 5;
+    //   /* Block comment attached
+    //    * to corge.  Leading asterisks
+    //    * will be removed. */
+    //   /* Block comment attached to
+    //    * grault. */
+    //   optional int32 grault = 6;
+    optional string leading_comments = 3;
+    optional string trailing_comments = 4;
+  }
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest.proto
new file mode 100644
index 0000000..6eb2d86
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest.proto
@@ -0,0 +1,719 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// A proto file we will use for unit testing.
+
+
+// Some generic_services option(s) added automatically.
+// See:  http://go/proto2-generic-services-default
+option cc_generic_services = true;     // auto-added
+option java_generic_services = true;   // auto-added
+option py_generic_services = true;     // auto-added
+
+import "google/protobuf/unittest_import.proto";
+
+// We don't put this in a package within proto2 because we need to make sure
+// that the generated code doesn't depend on being in the proto2 namespace.
+// In test_util.h we do "using namespace unittest = protobuf_unittest".
+package protobuf_unittest;
+
+// Protos optimized for SPEED use a strict superset of the generated code
+// of equivalent ones optimized for CODE_SIZE, so we should optimize all our
+// tests for speed unless explicitly testing code size optimization.
+option optimize_for = SPEED;
+
+option java_outer_classname = "UnittestProto";
+
+// This proto includes every type of field in both singular and repeated
+// forms.
+message TestAllTypes {
+  message NestedMessage {
+    // The field name "b" fails to compile in proto1 because it conflicts with
+    // a local variable named "b" in one of the generated methods.  Doh.
+    // This file needs to compile in proto1 to test backwards-compatibility.
+    optional int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+  }
+
+  // Singular
+  optional    int32 optional_int32    =  1;
+  optional    int64 optional_int64    =  2;
+  optional   uint32 optional_uint32   =  3;
+  optional   uint64 optional_uint64   =  4;
+  optional   sint32 optional_sint32   =  5;
+  optional   sint64 optional_sint64   =  6;
+  optional  fixed32 optional_fixed32  =  7;
+  optional  fixed64 optional_fixed64  =  8;
+  optional sfixed32 optional_sfixed32 =  9;
+  optional sfixed64 optional_sfixed64 = 10;
+  optional    float optional_float    = 11;
+  optional   double optional_double   = 12;
+  optional     bool optional_bool     = 13;
+  optional   string optional_string   = 14;
+  optional    bytes optional_bytes    = 15;
+
+  optional group OptionalGroup = 16 {
+    optional int32 a = 17;
+  }
+
+  optional NestedMessage                        optional_nested_message  = 18;
+  optional ForeignMessage                       optional_foreign_message = 19;
+  optional protobuf_unittest_import.ImportMessage optional_import_message  = 20;
+
+  optional NestedEnum                           optional_nested_enum     = 21;
+  optional ForeignEnum                          optional_foreign_enum    = 22;
+  optional protobuf_unittest_import.ImportEnum    optional_import_enum     = 23;
+
+  optional string optional_string_piece = 24 [ctype=STRING_PIECE];
+  optional string optional_cord = 25 [ctype=CORD];
+
+  // Defined in unittest_import_public.proto
+  optional protobuf_unittest_import.PublicImportMessage
+      optional_public_import_message = 26;
+
+  optional NestedMessage optional_lazy_message = 27 [lazy=true];
+
+  // Repeated
+  repeated    int32 repeated_int32    = 31;
+  repeated    int64 repeated_int64    = 32;
+  repeated   uint32 repeated_uint32   = 33;
+  repeated   uint64 repeated_uint64   = 34;
+  repeated   sint32 repeated_sint32   = 35;
+  repeated   sint64 repeated_sint64   = 36;
+  repeated  fixed32 repeated_fixed32  = 37;
+  repeated  fixed64 repeated_fixed64  = 38;
+  repeated sfixed32 repeated_sfixed32 = 39;
+  repeated sfixed64 repeated_sfixed64 = 40;
+  repeated    float repeated_float    = 41;
+  repeated   double repeated_double   = 42;
+  repeated     bool repeated_bool     = 43;
+  repeated   string repeated_string   = 44;
+  repeated    bytes repeated_bytes    = 45;
+
+  repeated group RepeatedGroup = 46 {
+    optional int32 a = 47;
+  }
+
+  repeated NestedMessage                        repeated_nested_message  = 48;
+  repeated ForeignMessage                       repeated_foreign_message = 49;
+  repeated protobuf_unittest_import.ImportMessage repeated_import_message  = 50;
+
+  repeated NestedEnum                           repeated_nested_enum     = 51;
+  repeated ForeignEnum                          repeated_foreign_enum    = 52;
+  repeated protobuf_unittest_import.ImportEnum    repeated_import_enum     = 53;
+
+  repeated string repeated_string_piece = 54 [ctype=STRING_PIECE];
+  repeated string repeated_cord = 55 [ctype=CORD];
+
+  repeated NestedMessage repeated_lazy_message = 57 [lazy=true];
+
+  // Singular with defaults
+  optional    int32 default_int32    = 61 [default =  41    ];
+  optional    int64 default_int64    = 62 [default =  42    ];
+  optional   uint32 default_uint32   = 63 [default =  43    ];
+  optional   uint64 default_uint64   = 64 [default =  44    ];
+  optional   sint32 default_sint32   = 65 [default = -45    ];
+  optional   sint64 default_sint64   = 66 [default =  46    ];
+  optional  fixed32 default_fixed32  = 67 [default =  47    ];
+  optional  fixed64 default_fixed64  = 68 [default =  48    ];
+  optional sfixed32 default_sfixed32 = 69 [default =  49    ];
+  optional sfixed64 default_sfixed64 = 70 [default = -50    ];
+  optional    float default_float    = 71 [default =  51.5  ];
+  optional   double default_double   = 72 [default =  52e3  ];
+  optional     bool default_bool     = 73 [default = true   ];
+  optional   string default_string   = 74 [default = "hello"];
+  optional    bytes default_bytes    = 75 [default = "world"];
+
+  optional NestedEnum  default_nested_enum  = 81 [default = BAR        ];
+  optional ForeignEnum default_foreign_enum = 82 [default = FOREIGN_BAR];
+  optional protobuf_unittest_import.ImportEnum
+      default_import_enum = 83 [default = IMPORT_BAR];
+
+  optional string default_string_piece = 84 [ctype=STRING_PIECE,default="abc"];
+  optional string default_cord = 85 [ctype=CORD,default="123"];
+}
+
+message TestDeprecatedFields {
+  optional int32 deprecated_int32 = 1 [deprecated=true];
+}
+
+// Define these after TestAllTypes to make sure the compiler can handle
+// that.
+message ForeignMessage {
+  optional int32 c = 1;
+}
+
+enum ForeignEnum {
+  FOREIGN_FOO = 4;
+  FOREIGN_BAR = 5;
+  FOREIGN_BAZ = 6;
+}
+
+message TestAllExtensions {
+  extensions 1 to max;
+}
+
+extend TestAllExtensions {
+  // Singular
+  optional    int32 optional_int32_extension    =  1;
+  optional    int64 optional_int64_extension    =  2;
+  optional   uint32 optional_uint32_extension   =  3;
+  optional   uint64 optional_uint64_extension   =  4;
+  optional   sint32 optional_sint32_extension   =  5;
+  optional   sint64 optional_sint64_extension   =  6;
+  optional  fixed32 optional_fixed32_extension  =  7;
+  optional  fixed64 optional_fixed64_extension  =  8;
+  optional sfixed32 optional_sfixed32_extension =  9;
+  optional sfixed64 optional_sfixed64_extension = 10;
+  optional    float optional_float_extension    = 11;
+  optional   double optional_double_extension   = 12;
+  optional     bool optional_bool_extension     = 13;
+  optional   string optional_string_extension   = 14;
+  optional    bytes optional_bytes_extension    = 15;
+
+  optional group OptionalGroup_extension = 16 {
+    optional int32 a = 17;
+  }
+
+  optional TestAllTypes.NestedMessage optional_nested_message_extension = 18;
+  optional ForeignMessage optional_foreign_message_extension = 19;
+  optional protobuf_unittest_import.ImportMessage
+    optional_import_message_extension = 20;
+
+  optional TestAllTypes.NestedEnum optional_nested_enum_extension = 21;
+  optional ForeignEnum optional_foreign_enum_extension = 22;
+  optional protobuf_unittest_import.ImportEnum
+    optional_import_enum_extension = 23;
+
+  optional string optional_string_piece_extension = 24 [ctype=STRING_PIECE];
+  optional string optional_cord_extension = 25 [ctype=CORD];
+
+  optional protobuf_unittest_import.PublicImportMessage
+    optional_public_import_message_extension = 26;
+
+  optional TestAllTypes.NestedMessage
+    optional_lazy_message_extension = 27 [lazy=true];
+
+  // Repeated
+  repeated    int32 repeated_int32_extension    = 31;
+  repeated    int64 repeated_int64_extension    = 32;
+  repeated   uint32 repeated_uint32_extension   = 33;
+  repeated   uint64 repeated_uint64_extension   = 34;
+  repeated   sint32 repeated_sint32_extension   = 35;
+  repeated   sint64 repeated_sint64_extension   = 36;
+  repeated  fixed32 repeated_fixed32_extension  = 37;
+  repeated  fixed64 repeated_fixed64_extension  = 38;
+  repeated sfixed32 repeated_sfixed32_extension = 39;
+  repeated sfixed64 repeated_sfixed64_extension = 40;
+  repeated    float repeated_float_extension    = 41;
+  repeated   double repeated_double_extension   = 42;
+  repeated     bool repeated_bool_extension     = 43;
+  repeated   string repeated_string_extension   = 44;
+  repeated    bytes repeated_bytes_extension    = 45;
+
+  repeated group RepeatedGroup_extension = 46 {
+    optional int32 a = 47;
+  }
+
+  repeated TestAllTypes.NestedMessage repeated_nested_message_extension = 48;
+  repeated ForeignMessage repeated_foreign_message_extension = 49;
+  repeated protobuf_unittest_import.ImportMessage
+    repeated_import_message_extension = 50;
+
+  repeated TestAllTypes.NestedEnum repeated_nested_enum_extension = 51;
+  repeated ForeignEnum repeated_foreign_enum_extension = 52;
+  repeated protobuf_unittest_import.ImportEnum
+    repeated_import_enum_extension = 53;
+
+  repeated string repeated_string_piece_extension = 54 [ctype=STRING_PIECE];
+  repeated string repeated_cord_extension = 55 [ctype=CORD];
+
+  repeated TestAllTypes.NestedMessage
+    repeated_lazy_message_extension = 57 [lazy=true];
+
+  // Singular with defaults
+  optional    int32 default_int32_extension    = 61 [default =  41    ];
+  optional    int64 default_int64_extension    = 62 [default =  42    ];
+  optional   uint32 default_uint32_extension   = 63 [default =  43    ];
+  optional   uint64 default_uint64_extension   = 64 [default =  44    ];
+  optional   sint32 default_sint32_extension   = 65 [default = -45    ];
+  optional   sint64 default_sint64_extension   = 66 [default =  46    ];
+  optional  fixed32 default_fixed32_extension  = 67 [default =  47    ];
+  optional  fixed64 default_fixed64_extension  = 68 [default =  48    ];
+  optional sfixed32 default_sfixed32_extension = 69 [default =  49    ];
+  optional sfixed64 default_sfixed64_extension = 70 [default = -50    ];
+  optional    float default_float_extension    = 71 [default =  51.5  ];
+  optional   double default_double_extension   = 72 [default =  52e3  ];
+  optional     bool default_bool_extension     = 73 [default = true   ];
+  optional   string default_string_extension   = 74 [default = "hello"];
+  optional    bytes default_bytes_extension    = 75 [default = "world"];
+
+  optional TestAllTypes.NestedEnum
+    default_nested_enum_extension = 81 [default = BAR];
+  optional ForeignEnum
+    default_foreign_enum_extension = 82 [default = FOREIGN_BAR];
+  optional protobuf_unittest_import.ImportEnum
+    default_import_enum_extension = 83 [default = IMPORT_BAR];
+
+  optional string default_string_piece_extension = 84 [ctype=STRING_PIECE,
+                                                       default="abc"];
+  optional string default_cord_extension = 85 [ctype=CORD, default="123"];
+}
+
+message TestNestedExtension {
+  extend TestAllExtensions {
+    // Check for bug where string extensions declared in tested scope did not
+    // compile.
+    optional string test = 1002 [default="test"];
+  }
+}
+
+// We have separate messages for testing required fields because it's
+// annoying to have to fill in required fields in TestProto in order to
+// do anything with it.  Note that we don't need to test every type of
+// required filed because the code output is basically identical to
+// optional fields for all types.
+message TestRequired {
+  required int32 a = 1;
+  optional int32 dummy2 = 2;
+  required int32 b = 3;
+
+  extend TestAllExtensions {
+    optional TestRequired single = 1000;
+    repeated TestRequired multi  = 1001;
+  }
+
+  // Pad the field count to 32 so that we can test that IsInitialized()
+  // properly checks multiple elements of has_bits_.
+  optional int32 dummy4  =  4;
+  optional int32 dummy5  =  5;
+  optional int32 dummy6  =  6;
+  optional int32 dummy7  =  7;
+  optional int32 dummy8  =  8;
+  optional int32 dummy9  =  9;
+  optional int32 dummy10 = 10;
+  optional int32 dummy11 = 11;
+  optional int32 dummy12 = 12;
+  optional int32 dummy13 = 13;
+  optional int32 dummy14 = 14;
+  optional int32 dummy15 = 15;
+  optional int32 dummy16 = 16;
+  optional int32 dummy17 = 17;
+  optional int32 dummy18 = 18;
+  optional int32 dummy19 = 19;
+  optional int32 dummy20 = 20;
+  optional int32 dummy21 = 21;
+  optional int32 dummy22 = 22;
+  optional int32 dummy23 = 23;
+  optional int32 dummy24 = 24;
+  optional int32 dummy25 = 25;
+  optional int32 dummy26 = 26;
+  optional int32 dummy27 = 27;
+  optional int32 dummy28 = 28;
+  optional int32 dummy29 = 29;
+  optional int32 dummy30 = 30;
+  optional int32 dummy31 = 31;
+  optional int32 dummy32 = 32;
+
+  required int32 c = 33;
+}
+
+message TestRequiredForeign {
+  optional TestRequired optional_message = 1;
+  repeated TestRequired repeated_message = 2;
+  optional int32 dummy = 3;
+}
+
+// Test that we can use NestedMessage from outside TestAllTypes.
+message TestForeignNested {
+  optional TestAllTypes.NestedMessage foreign_nested = 1;
+}
+
+// TestEmptyMessage is used to test unknown field support.
+message TestEmptyMessage {
+}
+
+// Like above, but declare all field numbers as potential extensions.  No
+// actual extensions should ever be defined for this type.
+message TestEmptyMessageWithExtensions {
+  extensions 1 to max;
+}
+
+message TestMultipleExtensionRanges {
+  extensions 42;
+  extensions 4143 to 4243;
+  extensions 65536 to max;
+}
+
+// Test that really large tag numbers don't break anything.
+message TestReallyLargeTagNumber {
+  // The largest possible tag number is 2^28 - 1, since the wire format uses
+  // three bits to communicate wire type.
+  optional int32 a = 1;
+  optional int32 bb = 268435455;
+}
+
+message TestRecursiveMessage {
+  optional TestRecursiveMessage a = 1;
+  optional int32 i = 2;
+}
+
+// Test that mutual recursion works.
+message TestMutualRecursionA {
+  optional TestMutualRecursionB bb = 1;
+}
+
+message TestMutualRecursionB {
+  optional TestMutualRecursionA a = 1;
+  optional int32 optional_int32 = 2;
+}
+
+// Test that groups have disjoint field numbers from their siblings and
+// parents.  This is NOT possible in proto1; only proto2.  When attempting
+// to compile with proto1, this will emit an error; so we only include it
+// in protobuf_unittest_proto.
+message TestDupFieldNumber {                        // NO_PROTO1
+  optional int32 a = 1;                             // NO_PROTO1
+  optional group Foo = 2 { optional int32 a = 1; }  // NO_PROTO1
+  optional group Bar = 3 { optional int32 a = 1; }  // NO_PROTO1
+}                                                   // NO_PROTO1
+
+// Additional messages for testing lazy fields.
+message TestEagerMessage {
+  optional TestAllTypes sub_message = 1 [lazy=false];
+}
+message TestLazyMessage {
+  optional TestAllTypes sub_message = 1 [lazy=true];
+}
+
+// Needed for a Python test.
+message TestNestedMessageHasBits {
+  message NestedMessage {
+    repeated int32 nestedmessage_repeated_int32 = 1;
+    repeated ForeignMessage nestedmessage_repeated_foreignmessage = 2;
+  }
+  optional NestedMessage optional_nested_message = 1;
+}
+
+
+// Test an enum that has multiple values with the same number.
+enum TestEnumWithDupValue {
+  option allow_alias = true;
+  FOO1 = 1;
+  BAR1 = 2;
+  BAZ = 3;
+  FOO2 = 1;
+  BAR2 = 2;
+}
+
+// Test an enum with large, unordered values.
+enum TestSparseEnum {
+  SPARSE_A = 123;
+  SPARSE_B = 62374;
+  SPARSE_C = 12589234;
+  SPARSE_D = -15;
+  SPARSE_E = -53452;
+  SPARSE_F = 0;
+  SPARSE_G = 2;
+}
+
+// Test message with CamelCase field names.  This violates Protocol Buffer
+// standard style.
+message TestCamelCaseFieldNames {
+  optional int32 PrimitiveField = 1;
+  optional string StringField = 2;
+  optional ForeignEnum EnumField = 3;
+  optional ForeignMessage MessageField = 4;
+  optional string StringPieceField = 5 [ctype=STRING_PIECE];
+  optional string CordField = 6 [ctype=CORD];
+
+  repeated int32 RepeatedPrimitiveField = 7;
+  repeated string RepeatedStringField = 8;
+  repeated ForeignEnum RepeatedEnumField = 9;
+  repeated ForeignMessage RepeatedMessageField = 10;
+  repeated string RepeatedStringPieceField = 11 [ctype=STRING_PIECE];
+  repeated string RepeatedCordField = 12 [ctype=CORD];
+}
+
+
+// We list fields out of order, to ensure that we're using field number and not
+// field index to determine serialization order.
+message TestFieldOrderings {
+  optional string my_string = 11;
+  extensions 2 to 10;
+  optional int64 my_int = 1;
+  extensions 12 to 100;
+  optional float my_float = 101;
+}
+
+
+extend TestFieldOrderings {
+  optional string my_extension_string = 50;
+  optional int32 my_extension_int = 5;
+}
+
+
+message TestExtremeDefaultValues {
+  optional bytes escaped_bytes = 1 [default = "\0\001\a\b\f\n\r\t\v\\\'\"\xfe"];
+  optional uint32 large_uint32 = 2 [default = 0xFFFFFFFF];
+  optional uint64 large_uint64 = 3 [default = 0xFFFFFFFFFFFFFFFF];
+  optional  int32 small_int32  = 4 [default = -0x7FFFFFFF];
+  optional  int64 small_int64  = 5 [default = -0x7FFFFFFFFFFFFFFF];
+  optional  int32 really_small_int32 = 21 [default = -0x80000000];
+  optional  int64 really_small_int64 = 22 [default = -0x8000000000000000];
+
+  // The default value here is UTF-8 for "\u1234".  (We could also just type
+  // the UTF-8 text directly into this text file rather than escape it, but
+  // lots of people use editors that would be confused by this.)
+  optional string utf8_string = 6 [default = "\341\210\264"];
+
+  // Tests for single-precision floating-point values.
+  optional float zero_float = 7 [default = 0];
+  optional float one_float = 8 [default = 1];
+  optional float small_float = 9 [default = 1.5];
+  optional float negative_one_float = 10 [default = -1];
+  optional float negative_float = 11 [default = -1.5];
+  // Using exponents
+  optional float large_float = 12 [default = 2E8];
+  optional float small_negative_float = 13 [default = -8e-28];
+
+  // Text for nonfinite floating-point values.
+  optional double inf_double = 14 [default = inf];
+  optional double neg_inf_double = 15 [default = -inf];
+  optional double nan_double = 16 [default = nan];
+  optional float inf_float = 17 [default = inf];
+  optional float neg_inf_float = 18 [default = -inf];
+  optional float nan_float = 19 [default = nan];
+
+  // Tests for C++ trigraphs.
+  // Trigraphs should be escaped in C++ generated files, but they should not be
+  // escaped for other languages.
+  // Note that in .proto file, "\?" is a valid way to escape ? in string
+  // literals.
+  optional string cpp_trigraph = 20 [default = "? \? ?? \?? \??? ??/ ?\?-"];
+
+  // String defaults containing the character '\000'
+  optional string string_with_zero       = 23 [default = "hel\000lo"];
+  optional  bytes bytes_with_zero        = 24 [default = "wor\000ld"];
+  optional string string_piece_with_zero = 25 [ctype=STRING_PIECE,
+                                               default="ab\000c"];
+  optional string cord_with_zero         = 26 [ctype=CORD,
+                                               default="12\0003"];
+}
+
+message SparseEnumMessage {
+  optional TestSparseEnum sparse_enum = 1;
+}
+
+// Test String and Bytes: string is for valid UTF-8 strings
+message OneString {
+  optional string data = 1;
+}
+
+message MoreString {
+  repeated string data = 1;
+}
+
+message OneBytes {
+  optional bytes data = 1;
+}
+
+message MoreBytes {
+  repeated bytes data = 1;
+}
+
+
+// Test messages for packed fields
+
+message TestPackedTypes {
+  repeated    int32 packed_int32    =  90 [packed = true];
+  repeated    int64 packed_int64    =  91 [packed = true];
+  repeated   uint32 packed_uint32   =  92 [packed = true];
+  repeated   uint64 packed_uint64   =  93 [packed = true];
+  repeated   sint32 packed_sint32   =  94 [packed = true];
+  repeated   sint64 packed_sint64   =  95 [packed = true];
+  repeated  fixed32 packed_fixed32  =  96 [packed = true];
+  repeated  fixed64 packed_fixed64  =  97 [packed = true];
+  repeated sfixed32 packed_sfixed32 =  98 [packed = true];
+  repeated sfixed64 packed_sfixed64 =  99 [packed = true];
+  repeated    float packed_float    = 100 [packed = true];
+  repeated   double packed_double   = 101 [packed = true];
+  repeated     bool packed_bool     = 102 [packed = true];
+  repeated ForeignEnum packed_enum  = 103 [packed = true];
+}
+
+// A message with the same fields as TestPackedTypes, but without packing. Used
+// to test packed <-> unpacked wire compatibility.
+message TestUnpackedTypes {
+  repeated    int32 unpacked_int32    =  90 [packed = false];
+  repeated    int64 unpacked_int64    =  91 [packed = false];
+  repeated   uint32 unpacked_uint32   =  92 [packed = false];
+  repeated   uint64 unpacked_uint64   =  93 [packed = false];
+  repeated   sint32 unpacked_sint32   =  94 [packed = false];
+  repeated   sint64 unpacked_sint64   =  95 [packed = false];
+  repeated  fixed32 unpacked_fixed32  =  96 [packed = false];
+  repeated  fixed64 unpacked_fixed64  =  97 [packed = false];
+  repeated sfixed32 unpacked_sfixed32 =  98 [packed = false];
+  repeated sfixed64 unpacked_sfixed64 =  99 [packed = false];
+  repeated    float unpacked_float    = 100 [packed = false];
+  repeated   double unpacked_double   = 101 [packed = false];
+  repeated     bool unpacked_bool     = 102 [packed = false];
+  repeated ForeignEnum unpacked_enum  = 103 [packed = false];
+}
+
+message TestPackedExtensions {
+  extensions 1 to max;
+}
+
+extend TestPackedExtensions {
+  repeated    int32 packed_int32_extension    =  90 [packed = true];
+  repeated    int64 packed_int64_extension    =  91 [packed = true];
+  repeated   uint32 packed_uint32_extension   =  92 [packed = true];
+  repeated   uint64 packed_uint64_extension   =  93 [packed = true];
+  repeated   sint32 packed_sint32_extension   =  94 [packed = true];
+  repeated   sint64 packed_sint64_extension   =  95 [packed = true];
+  repeated  fixed32 packed_fixed32_extension  =  96 [packed = true];
+  repeated  fixed64 packed_fixed64_extension  =  97 [packed = true];
+  repeated sfixed32 packed_sfixed32_extension =  98 [packed = true];
+  repeated sfixed64 packed_sfixed64_extension =  99 [packed = true];
+  repeated    float packed_float_extension    = 100 [packed = true];
+  repeated   double packed_double_extension   = 101 [packed = true];
+  repeated     bool packed_bool_extension     = 102 [packed = true];
+  repeated ForeignEnum packed_enum_extension  = 103 [packed = true];
+}
+
+// Used by ExtensionSetTest/DynamicExtensions.  The test actually builds
+// a set of extensions to TestAllExtensions dynamically, based on the fields
+// of this message type.
+message TestDynamicExtensions {
+  enum DynamicEnumType {
+    DYNAMIC_FOO = 2200;
+    DYNAMIC_BAR = 2201;
+    DYNAMIC_BAZ = 2202;
+  }
+  message DynamicMessageType {
+    optional int32 dynamic_field = 2100;
+  }
+
+  optional fixed32 scalar_extension = 2000;
+  optional ForeignEnum enum_extension = 2001;
+  optional DynamicEnumType dynamic_enum_extension = 2002;
+
+  optional ForeignMessage message_extension = 2003;
+  optional DynamicMessageType dynamic_message_extension = 2004;
+
+  repeated string repeated_extension = 2005;
+  repeated sint32 packed_extension = 2006 [packed = true];
+}
+
+message TestRepeatedScalarDifferentTagSizes {
+  // Parsing repeated fixed size values used to fail. This message needs to be
+  // used in order to get a tag of the right size; all of the repeated fields
+  // in TestAllTypes didn't trigger the check.
+  repeated fixed32 repeated_fixed32 = 12;
+  // Check for a varint type, just for good measure.
+  repeated int32   repeated_int32   = 13;
+
+  // These have two-byte tags.
+  repeated fixed64 repeated_fixed64 = 2046;
+  repeated int64   repeated_int64   = 2047;
+
+  // Three byte tags.
+  repeated float   repeated_float   = 262142;
+  repeated uint64  repeated_uint64  = 262143;
+}
+
+// Test that if an optional or required message/group field appears multiple
+// times in the input, they need to be merged.
+message TestParsingMerge {
+  // RepeatedFieldsGenerator defines matching field types as TestParsingMerge,
+  // except that all fields are repeated. In the tests, we will serialize the
+  // RepeatedFieldsGenerator to bytes, and parse the bytes to TestParsingMerge.
+  // Repeated fields in RepeatedFieldsGenerator are expected to be merged into
+  // the corresponding required/optional fields in TestParsingMerge.
+  message RepeatedFieldsGenerator {
+    repeated TestAllTypes field1 = 1;
+    repeated TestAllTypes field2 = 2;
+    repeated TestAllTypes field3 = 3;
+    repeated group Group1 = 10 {
+      optional TestAllTypes field1 = 11;
+    }
+    repeated group Group2 = 20 {
+      optional TestAllTypes field1 = 21;
+    }
+    repeated TestAllTypes ext1 = 1000;
+    repeated TestAllTypes ext2 = 1001;
+  }
+  required TestAllTypes required_all_types = 1;
+  optional TestAllTypes optional_all_types = 2;
+  repeated TestAllTypes repeated_all_types = 3;
+  optional group OptionalGroup = 10 {
+    optional TestAllTypes optional_group_all_types = 11;
+  }
+  repeated group RepeatedGroup = 20 {
+    optional TestAllTypes repeated_group_all_types = 21;
+  }
+  extensions 1000 to max;
+  extend TestParsingMerge {
+    optional TestAllTypes optional_ext = 1000;
+    repeated TestAllTypes repeated_ext = 1001;
+  }
+}
+
+message TestCommentInjectionMessage {
+  // */ <- This should not close the generated doc comment
+  optional string a = 1 [default="*/ <- Neither should this."];
+}
+
+
+// Test that RPC services work.
+message FooRequest  {}
+message FooResponse {}
+
+message FooClientMessage {}
+message FooServerMessage{}
+
+service TestService {
+  rpc Foo(FooRequest) returns (FooResponse);
+  rpc Bar(BarRequest) returns (BarResponse);
+}
+
+
+message BarRequest  {}
+message BarResponse {}
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_custom_options.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_custom_options.proto
new file mode 100644
index 0000000..e591d29
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_custom_options.proto
@@ -0,0 +1,387 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: benjy@google.com (Benjy Weinberger)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// A proto file used to test the "custom options" feature of proto2.
+
+
+// Some generic_services option(s) added automatically.
+// See:  http://go/proto2-generic-services-default
+option cc_generic_services = true;     // auto-added
+option java_generic_services = true;   // auto-added
+option py_generic_services = true;
+
+// A custom file option (defined below).
+option (file_opt1) = 9876543210;
+
+import "google/protobuf/descriptor.proto";
+
+// We don't put this in a package within proto2 because we need to make sure
+// that the generated code doesn't depend on being in the proto2 namespace.
+package protobuf_unittest;
+
+
+// Some simple test custom options of various types.
+
+extend google.protobuf.FileOptions {
+  optional uint64 file_opt1 = 7736974;
+}
+
+extend google.protobuf.MessageOptions {
+  optional int32 message_opt1 = 7739036;
+}
+
+extend google.protobuf.FieldOptions {
+  optional fixed64 field_opt1 = 7740936;
+  // This is useful for testing that we correctly register default values for
+  // extension options.
+  optional int32 field_opt2 = 7753913 [default=42];
+}
+
+extend google.protobuf.EnumOptions {
+  optional sfixed32 enum_opt1 = 7753576;
+}
+
+extend google.protobuf.EnumValueOptions {
+  optional int32 enum_value_opt1 = 1560678;
+}
+
+extend google.protobuf.ServiceOptions {
+  optional sint64 service_opt1 = 7887650;
+}
+
+enum MethodOpt1 {
+  METHODOPT1_VAL1 = 1;
+  METHODOPT1_VAL2 = 2;
+}
+
+extend google.protobuf.MethodOptions {
+  optional MethodOpt1 method_opt1 = 7890860;
+}
+
+// A test message with custom options at all possible locations (and also some
+// regular options, to make sure they interact nicely).
+message TestMessageWithCustomOptions {
+  option message_set_wire_format = false;
+
+  option (message_opt1) = -56;
+
+  optional string field1 = 1 [ctype=CORD,
+                              (field_opt1)=8765432109];
+
+  enum AnEnum {
+    option (enum_opt1) = -789;
+
+    ANENUM_VAL1 = 1;
+    ANENUM_VAL2 = 2 [(enum_value_opt1) = 123];
+  }
+}
+
+
+// A test RPC service with custom options at all possible locations (and also
+// some regular options, to make sure they interact nicely).
+message CustomOptionFooRequest {
+}
+
+message CustomOptionFooResponse {
+}
+
+message CustomOptionFooClientMessage {
+}
+
+message CustomOptionFooServerMessage {
+}
+
+service TestServiceWithCustomOptions {
+  option (service_opt1) = -9876543210;
+
+  rpc Foo(CustomOptionFooRequest) returns (CustomOptionFooResponse) {
+    option (method_opt1) = METHODOPT1_VAL2;
+  }
+}
+
+
+
+// Options of every possible field type, so we can test them all exhaustively.
+
+message DummyMessageContainingEnum {
+  enum TestEnumType {
+    TEST_OPTION_ENUM_TYPE1 = 22;
+    TEST_OPTION_ENUM_TYPE2 = -23;
+  }
+}
+
+message DummyMessageInvalidAsOptionType {
+}
+
+extend google.protobuf.MessageOptions {
+  optional         bool     bool_opt = 7706090;
+  optional        int32    int32_opt = 7705709;
+  optional        int64    int64_opt = 7705542;
+  optional       uint32   uint32_opt = 7704880;
+  optional       uint64   uint64_opt = 7702367;
+  optional       sint32   sint32_opt = 7701568;
+  optional       sint64   sint64_opt = 7700863;
+  optional      fixed32  fixed32_opt = 7700307;
+  optional      fixed64  fixed64_opt = 7700194;
+  optional     sfixed32 sfixed32_opt = 7698645;
+  optional     sfixed64 sfixed64_opt = 7685475;
+  optional        float    float_opt = 7675390;
+  optional       double   double_opt = 7673293;
+  optional       string   string_opt = 7673285;
+  optional        bytes    bytes_opt = 7673238;
+  optional DummyMessageContainingEnum.TestEnumType enum_opt = 7673233;
+  optional DummyMessageInvalidAsOptionType message_type_opt = 7665967;
+}
+
+message CustomOptionMinIntegerValues {
+  option     (bool_opt) = false;
+  option    (int32_opt) = -0x80000000;
+  option    (int64_opt) = -0x8000000000000000;
+  option   (uint32_opt) = 0;
+  option   (uint64_opt) = 0;
+  option   (sint32_opt) = -0x80000000;
+  option   (sint64_opt) = -0x8000000000000000;
+  option  (fixed32_opt) = 0;
+  option  (fixed64_opt) = 0;
+  option (sfixed32_opt) = -0x80000000;
+  option (sfixed64_opt) = -0x8000000000000000;
+}
+
+message CustomOptionMaxIntegerValues {
+  option     (bool_opt) = true;
+  option    (int32_opt) = 0x7FFFFFFF;
+  option    (int64_opt) = 0x7FFFFFFFFFFFFFFF;
+  option   (uint32_opt) = 0xFFFFFFFF;
+  option   (uint64_opt) = 0xFFFFFFFFFFFFFFFF;
+  option   (sint32_opt) = 0x7FFFFFFF;
+  option   (sint64_opt) = 0x7FFFFFFFFFFFFFFF;
+  option  (fixed32_opt) = 0xFFFFFFFF;
+  option  (fixed64_opt) = 0xFFFFFFFFFFFFFFFF;
+  option (sfixed32_opt) = 0x7FFFFFFF;
+  option (sfixed64_opt) = 0x7FFFFFFFFFFFFFFF;
+}
+
+message CustomOptionOtherValues {
+  option  (int32_opt) = -100;  // To test sign-extension.
+  option  (float_opt) = 12.3456789;
+  option (double_opt) = 1.234567890123456789;
+  option (string_opt) = "Hello, \"World\"";
+  option  (bytes_opt) = "Hello\0World";
+  option   (enum_opt) = TEST_OPTION_ENUM_TYPE2;
+}
+
+message SettingRealsFromPositiveInts {
+  option  (float_opt) = 12;
+  option (double_opt) = 154;
+}
+
+message SettingRealsFromNegativeInts {
+  option  (float_opt) = -12;
+  option  (double_opt) = -154;
+}
+
+// Options of complex message types, themselves combined and extended in
+// various ways.
+
+message ComplexOptionType1 {
+  optional int32 foo = 1;
+  optional int32 foo2 = 2;
+  optional int32 foo3 = 3;
+
+  extensions 100 to max;
+}
+
+message ComplexOptionType2 {
+  optional ComplexOptionType1 bar = 1;
+  optional int32 baz = 2;
+
+  message ComplexOptionType4 {
+    optional int32 waldo = 1;
+
+    extend google.protobuf.MessageOptions {
+      optional ComplexOptionType4 complex_opt4 = 7633546;
+    }
+  }
+
+  optional ComplexOptionType4 fred = 3;
+
+  extensions 100 to max;
+}
+
+message ComplexOptionType3 {
+  optional int32 qux = 1;
+
+  optional group ComplexOptionType5 = 2 {
+    optional int32 plugh = 3;
+  }
+}
+
+extend ComplexOptionType1 {
+  optional int32 quux = 7663707;
+  optional ComplexOptionType3 corge = 7663442;
+}
+
+extend ComplexOptionType2 {
+  optional int32 grault = 7650927;
+  optional ComplexOptionType1 garply = 7649992;
+}
+
+extend google.protobuf.MessageOptions {
+  optional protobuf_unittest.ComplexOptionType1 complex_opt1 = 7646756;
+  optional ComplexOptionType2 complex_opt2 = 7636949;
+  optional ComplexOptionType3 complex_opt3 = 7636463;
+  optional group ComplexOpt6 = 7595468 {
+    optional int32 xyzzy = 7593951;
+  }
+}
+
+// Note that we try various different ways of naming the same extension.
+message VariousComplexOptions {
+  option (.protobuf_unittest.complex_opt1).foo = 42;
+  option (protobuf_unittest.complex_opt1).(.protobuf_unittest.quux) = 324;
+  option (.protobuf_unittest.complex_opt1).(protobuf_unittest.corge).qux = 876;
+  option (complex_opt2).baz = 987;
+  option (complex_opt2).(grault) = 654;
+  option (complex_opt2).bar.foo = 743;
+  option (complex_opt2).bar.(quux) = 1999;
+  option (complex_opt2).bar.(protobuf_unittest.corge).qux = 2008;
+  option (complex_opt2).(garply).foo = 741;
+  option (complex_opt2).(garply).(.protobuf_unittest.quux) = 1998;
+  option (complex_opt2).(protobuf_unittest.garply).(corge).qux = 2121;
+  option (ComplexOptionType2.ComplexOptionType4.complex_opt4).waldo = 1971;
+  option (complex_opt2).fred.waldo = 321;
+  option (protobuf_unittest.complex_opt3).qux = 9;
+  option (complex_opt3).complexoptiontype5.plugh = 22;
+  option (complexopt6).xyzzy = 24;
+}
+
+// ------------------------------------------------------
+// Definitions for testing aggregate option parsing.
+// See descriptor_unittest.cc.
+
+message AggregateMessageSet {
+  option message_set_wire_format = true;
+  extensions 4 to max;
+}
+
+message AggregateMessageSetElement {
+  extend AggregateMessageSet {
+    optional AggregateMessageSetElement message_set_extension = 15447542;
+  }
+  optional string s = 1;
+}
+
+// A helper type used to test aggregate option parsing
+message Aggregate {
+  optional int32 i = 1;
+  optional string s = 2;
+
+  // A nested object
+  optional Aggregate sub = 3;
+
+  // To test the parsing of extensions inside aggregate values
+  optional google.protobuf.FileOptions file = 4;
+  extend google.protobuf.FileOptions {
+    optional Aggregate nested = 15476903;
+  }
+
+  // An embedded message set
+  optional AggregateMessageSet mset = 5;
+}
+
+// Allow Aggregate to be used as an option at all possible locations
+// in the .proto grammer.
+extend google.protobuf.FileOptions      { optional Aggregate fileopt    = 15478479; }
+extend google.protobuf.MessageOptions   { optional Aggregate msgopt     = 15480088; }
+extend google.protobuf.FieldOptions     { optional Aggregate fieldopt   = 15481374; }
+extend google.protobuf.EnumOptions      { optional Aggregate enumopt    = 15483218; }
+extend google.protobuf.EnumValueOptions { optional Aggregate enumvalopt = 15486921; }
+extend google.protobuf.ServiceOptions   { optional Aggregate serviceopt = 15497145; }
+extend google.protobuf.MethodOptions    { optional Aggregate methodopt  = 15512713; }
+
+// Try using AggregateOption at different points in the proto grammar
+option (fileopt) = {
+  s: 'FileAnnotation'
+  // Also test the handling of comments
+  /* of both types */ i: 100
+
+  sub { s: 'NestedFileAnnotation' }
+
+  // Include a google.protobuf.FileOptions and recursively extend it with
+  // another fileopt.
+  file {
+    [protobuf_unittest.fileopt] {
+      s:'FileExtensionAnnotation'
+    }
+  }
+
+  // A message set inside an option value
+  mset {
+    [protobuf_unittest.AggregateMessageSetElement.message_set_extension] {
+      s: 'EmbeddedMessageSetElement'
+    }
+  }
+};
+
+message AggregateMessage {
+  option (msgopt) = { i:101 s:'MessageAnnotation' };
+  optional int32 fieldname = 1 [(fieldopt) = { s:'FieldAnnotation' }];
+}
+
+service AggregateService {
+  option (serviceopt) = { s:'ServiceAnnotation' };
+  rpc Method (AggregateMessage) returns (AggregateMessage) {
+    option (methodopt) = { s:'MethodAnnotation' };
+  }
+}
+
+enum AggregateEnum {
+  option (enumopt) = { s:'EnumAnnotation' };
+  VALUE = 1 [(enumvalopt) = { s:'EnumValueAnnotation' }];
+}
+
+// Test custom options for nested type.
+message NestedOptionType {
+  message NestedMessage {
+    option (message_opt1) = 1001;
+    optional int32 nested_field = 1 [(field_opt1) = 1002];
+  }
+  enum NestedEnum {
+    option (enum_opt1) = 1003;
+    NESTED_ENUM_VALUE = 1 [(enum_value_opt1) = 1004];
+  }
+  extend google.protobuf.FileOptions {
+    optional int32 nested_extension = 7912573 [(field_opt2) = 1005];
+  }
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_import.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_import.proto
new file mode 100644
index 0000000..c115b11
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_import.proto
@@ -0,0 +1,64 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// A proto file which is imported by unittest.proto to test importing.
+
+
+// We don't put this in a package within proto2 because we need to make sure
+// that the generated code doesn't depend on being in the proto2 namespace.
+// In test_util.h we do
+// "using namespace unittest_import = protobuf_unittest_import".
+package protobuf_unittest_import;
+
+option optimize_for = SPEED;
+
+// Excercise the java_package option.
+option java_package = "com.google.protobuf.test";
+
+// Do not set a java_outer_classname here to verify that Proto2 works without
+// one.
+
+// Test public import
+import public "google/protobuf/unittest_import_public.proto";
+
+message ImportMessage {
+  optional int32 d = 1;
+}
+
+enum ImportEnum {
+  IMPORT_FOO = 7;
+  IMPORT_BAR = 8;
+  IMPORT_BAZ = 9;
+}
+
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_import_public.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_import_public.proto
new file mode 100644
index 0000000..ea5d1b1
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_import_public.proto
@@ -0,0 +1,40 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: liujisi@google.com (Pherl Liu)
+
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.test";
+
+message PublicImportMessage {
+  optional int32 e = 1;
+}
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_mset.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_mset.proto
new file mode 100644
index 0000000..3497f09
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_mset.proto
@@ -0,0 +1,72 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// This file contains messages for testing message_set_wire_format.
+
+package protobuf_unittest;
+
+option optimize_for = SPEED;
+
+// A message with message_set_wire_format.
+message TestMessageSet {
+  option message_set_wire_format = true;
+  extensions 4 to max;
+}
+
+message TestMessageSetContainer {
+  optional TestMessageSet message_set = 1;
+}
+
+message TestMessageSetExtension1 {
+  extend TestMessageSet {
+    optional TestMessageSetExtension1 message_set_extension = 1545008;
+  }
+  optional int32 i = 15;
+}
+
+message TestMessageSetExtension2 {
+  extend TestMessageSet {
+    optional TestMessageSetExtension2 message_set_extension = 1547769;
+  }
+  optional string str = 25;
+}
+
+// MessageSet wire format is equivalent to this.
+message RawMessageSet {
+  repeated group Item = 1 {
+    required int32 type_id = 2;
+    required bytes message = 3;
+  }
+}
+
diff --git a/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_no_generic_services.proto b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_no_generic_services.proto
new file mode 100644
index 0000000..cffb412
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/protos/src/proto/google/protobuf/unittest_no_generic_services.proto
@@ -0,0 +1,52 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+
+package google.protobuf.no_generic_services_test;
+
+// *_generic_services are false by default.
+
+message TestMessage {
+  optional int32 a = 1;
+  extensions 1000 to max;
+}
+
+enum TestEnum {
+  FOO = 1;
+}
+
+extend TestMessage {
+  optional int32 test_extension = 1000;
+}
+
+service TestService {
+  rpc Foo(TestMessage) returns(TestMessage);
+}
diff --git a/python/compatibility_tests/v2.5.0/setup.py b/python/compatibility_tests/v2.5.0/setup.py
new file mode 100755
index 0000000..b41d54d
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/setup.py
@@ -0,0 +1,87 @@
+#! /usr/bin/env python
+#
+import glob
+import os
+import subprocess
+import sys
+
+from setuptools import setup, Extension, find_packages
+
+if sys.version_info[0] == 3:
+  # Python 3
+  from distutils.command.build_py import build_py_2to3 as _build_py
+else:
+  # Python 2
+  from distutils.command.build_py import build_py as _build_py
+from distutils.spawn import find_executable
+
+def generate_proto(source, code_gen):
+  """Invokes the Protocol Compiler to generate a _pb2.py from the given
+  .proto file."""
+  output = source.replace(".proto", "_pb2.py").replace("protos/src/proto/", "").replace("protos/python/", "")
+
+  if not os.path.exists(source):
+    sys.stderr.write("Can't find required file: %s\n" % source)
+    sys.exit(-1)
+
+  protoc_command = [ code_gen, "-Iprotos/src/proto", "-Iprotos/python", "--python_out=.", source ]
+  if subprocess.call(protoc_command) != 0:
+    sys.exit(-1)
+
+class build_py(_build_py):
+  def run(self):
+    # generate .proto file
+    protoc_1 = "./protoc_1"
+    protoc_2 = "./protoc_2"
+    generate_proto("protos/src/proto/google/protobuf/unittest.proto", protoc_2)
+    generate_proto("protos/src/proto/google/protobuf/unittest_custom_options.proto", protoc_1)
+    generate_proto("protos/src/proto/google/protobuf/unittest_import.proto", protoc_1)
+    generate_proto("protos/src/proto/google/protobuf/unittest_import_public.proto", protoc_1)
+    generate_proto("protos/src/proto/google/protobuf/unittest_mset.proto", protoc_1)
+    generate_proto("protos/src/proto/google/protobuf/unittest_no_generic_services.proto", protoc_1)
+    generate_proto("protos/python/google/protobuf/internal/factory_test1.proto", protoc_1)
+    generate_proto("protos/python/google/protobuf/internal/factory_test2.proto", protoc_1)
+    generate_proto("protos/python/google/protobuf/internal/more_extensions.proto", protoc_1)
+    generate_proto("protos/python/google/protobuf/internal/more_extensions_dynamic.proto", protoc_1)
+    generate_proto("protos/python/google/protobuf/internal/more_messages.proto", protoc_1)
+    generate_proto("protos/python/google/protobuf/internal/test_bad_identifiers.proto", protoc_1)
+
+    # _build_py is an old-style class, so super() doesn't work.
+    _build_py.run(self)
+
+if __name__ == '__main__':
+  # Keep this list of dependencies in sync with tox.ini.
+  install_requires = ['six>=1.9', 'setuptools']
+  if sys.version_info <= (2,7):
+    install_requires.append('ordereddict')
+    install_requires.append('unittest2')
+
+  setup(
+      name='protobuf',
+      description='Protocol Buffers',
+      download_url='https://github.com/google/protobuf/releases',
+      long_description="Protocol Buffers are Google's data interchange format",
+      url='https://developers.google.com/protocol-buffers/',
+      maintainer='protobuf@googlegroups.com',
+      maintainer_email='protobuf@googlegroups.com',
+      license='3-Clause BSD License',
+      classifiers=[
+        "Programming Language :: Python",
+        "Programming Language :: Python :: 2",
+        "Programming Language :: Python :: 2.6",
+        "Programming Language :: Python :: 2.7",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.3",
+        "Programming Language :: Python :: 3.4",
+        ],
+      packages=find_packages(
+          exclude=[
+              'import_test_package',
+          ],
+      ),
+      test_suite='tests.google.protobuf.internal',
+      cmdclass={
+          'build_py': build_py,
+      },
+      install_requires=install_requires,
+  )
diff --git a/python/compatibility_tests/v2.5.0/test.sh b/python/compatibility_tests/v2.5.0/test.sh
new file mode 100755
index 0000000..78c16ad
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/test.sh
@@ -0,0 +1,104 @@
+#!/bin/bash
+
+set -ex
+
+# Change to the script's directory.
+cd $(dirname $0)
+
+# Version of the tests (i.e., the version of protobuf from where we extracted
+# these tests).
+TEST_VERSION=2.5.0
+
+# The old version of protobuf that we are testing compatibility against. This
+# is usually the same as TEST_VERSION (i.e., we use the tests extracted from
+# that version to test compatibility of the newest runtime against it), but it
+# is also possible to use this same test set to test the compatibiilty of the
+# latest version against other versions.
+case "$1" in
+  ""|2.5.0)
+    OLD_VERSION=2.5.0
+    OLD_VERSION_PROTOC=https://github.com/xfxyjwf/protobuf-compiler-release/raw/master/v2.5.0/linux/protoc
+    ;;
+  2.6.1)
+    OLD_VERSION=2.6.1
+    OLD_VERSION_PROTOC=http://repo1.maven.org/maven2/com/google/protobuf/protoc/2.6.1-build2/protoc-2.6.1-build2-linux-x86_64.exe
+    ;;
+  3.0.0-beta-1)
+    OLD_VERSION=3.0.0-beta-1
+    OLD_VERSION_PROTOC=http://repo1.maven.org/maven2/com/google/protobuf/protoc/3.0.0-beta-1/protoc-3.0.0-beta-1-linux-x86_64.exe
+    ;;
+  3.0.0-beta-2)
+    OLD_VERSION=3.0.0-beta-2
+    OLD_VERSION_PROTOC=http://repo1.maven.org/maven2/com/google/protobuf/protoc/3.0.0-beta-2/protoc-3.0.0-beta-2-linux-x86_64.exe
+    ;;
+  3.0.0-beta-3)
+    OLD_VERSION=3.0.0-beta-3
+    OLD_VERSION_PROTOC=http://repo1.maven.org/maven2/com/google/protobuf/protoc/3.0.0-beta-3/protoc-3.0.0-beta-3-linux-x86_64.exe
+    ;;
+  3.0.0-beta-4)
+    OLD_VERSION=3.0.0-beta-4
+    OLD_VERSION_PROTOC=http://repo1.maven.org/maven2/com/google/protobuf/protoc/3.0.0-beta-4/protoc-3.0.0-beta-4-linux-x86_64.exe
+    ;;
+  *)
+    echo "[ERROR]: Unknown version number: $1"
+    exit 1
+    ;;
+esac
+
+# Extract the latest protobuf version number.
+VERSION_NUMBER=`grep "^__version__ = '.*'" ../../google/protobuf/__init__.py | sed "s|__version__ = '\(.*\)'|\1|"`
+
+echo "Running compatibility tests between $VERSION_NUMBER and $OLD_VERSION"
+
+# Check protoc
+[ -f ../../../src/protoc ] || {
+  echo "[ERROR]: Please build protoc first."
+  exit 1
+}
+
+# Test source compatibility. In these tests we recompile everything against
+# the new runtime (including old version generated code).
+rm google -f -r
+mkdir -p google/protobuf/internal
+# Build and copy the new runtime
+cd ../../
+python setup.py build
+cp google/protobuf/*.py compatibility_tests/v2.5.0/google/protobuf/
+cp google/protobuf/internal/*.py compatibility_tests/v2.5.0/google/protobuf/internal/
+cd compatibility_tests/v2.5.0
+cp tests/google/protobuf/internal/test_util.py google/protobuf/internal/
+cp google/protobuf/__init__.py google/
+
+# Download old version protoc compiler (for linux)
+wget $OLD_VERSION_PROTOC -O old_protoc
+chmod +x old_protoc
+
+# Test A.1:
+#   proto set 1: use old version
+#   proto set 2 which may import protos in set 1: use old version
+cp old_protoc protoc_1
+cp old_protoc protoc_2
+python setup.py build
+python setup.py test
+
+# Test A.2:
+#   proto set 1: use new version
+#   proto set 2 which may import protos in set 1: use old version
+cp ../../../src/protoc protoc_1
+cp old_protoc protoc_2
+python setup.py build
+python setup.py test
+
+# Test A.3:
+#   proto set 1: use old version
+#   proto set 2 which may import protos in set 1: use new version
+cp old_protoc protoc_1
+cp ../../../src/protoc protoc_2
+python setup.py build
+python setup.py test
+
+rm google -r -f
+rm build -r -f
+rm protoc_1
+rm protoc_2
+rm old_protoc
diff --git a/python/compatibility_tests/v2.5.0/tests/__init__.py b/python/compatibility_tests/v2.5.0/tests/__init__.py
new file mode 100644
index 0000000..5585614
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/__init__.py
@@ -0,0 +1,4 @@
+try:
+  __import__('pkg_resources').declare_namespace(__name__)
+except ImportError:
+  __path__ = __import__('pkgutil').extend_path(__path__, __name__)
diff --git a/python/compatibility_tests/v2.5.0/tests/google/__init__.py b/python/compatibility_tests/v2.5.0/tests/google/__init__.py
new file mode 100644
index 0000000..5585614
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/__init__.py
@@ -0,0 +1,4 @@
+try:
+  __import__('pkg_resources').declare_namespace(__name__)
+except ImportError:
+  __path__ = __import__('pkgutil').extend_path(__path__, __name__)
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/__init__.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/__init__.py
new file mode 100644
index 0000000..5585614
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/__init__.py
@@ -0,0 +1,4 @@
+try:
+  __import__('pkg_resources').declare_namespace(__name__)
+except ImportError:
+  __path__ = __import__('pkgutil').extend_path(__path__, __name__)
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/__init__.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/__init__.py
new file mode 100644
index 0000000..64c6956
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/__init__.py
@@ -0,0 +1,37 @@
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# https://developers.google.com/protocol-buffers/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# Copyright 2007 Google Inc. All Rights Reserved.
+
+if __name__ != '__main__':
+  try:
+    __import__('pkg_resources').declare_namespace(__name__)
+  except ImportError:
+    __path__ = __import__('pkgutil').extend_path(__path__, __name__)
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/descriptor_test.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/descriptor_test.py
new file mode 100755
index 0000000..c74f882
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/descriptor_test.py
@@ -0,0 +1,613 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Unittest for google.protobuf.internal.descriptor."""
+
+__author__ = 'robinson@google.com (Will Robinson)'
+
+import unittest
+from google.protobuf import unittest_custom_options_pb2
+from google.protobuf import unittest_import_pb2
+from google.protobuf import unittest_pb2
+from google.protobuf import descriptor_pb2
+from google.protobuf import descriptor
+from google.protobuf import text_format
+
+
+TEST_EMPTY_MESSAGE_DESCRIPTOR_ASCII = """
+name: 'TestEmptyMessage'
+"""
+
+
+class DescriptorTest(unittest.TestCase):
+
+  def setUp(self):
+    self.my_file = descriptor.FileDescriptor(
+        name='some/filename/some.proto',
+        package='protobuf_unittest'
+        )
+    self.my_enum = descriptor.EnumDescriptor(
+        name='ForeignEnum',
+        full_name='protobuf_unittest.ForeignEnum',
+        filename=None,
+        file=self.my_file,
+        values=[
+          descriptor.EnumValueDescriptor(name='FOREIGN_FOO', index=0, number=4),
+          descriptor.EnumValueDescriptor(name='FOREIGN_BAR', index=1, number=5),
+          descriptor.EnumValueDescriptor(name='FOREIGN_BAZ', index=2, number=6),
+        ])
+    self.my_message = descriptor.Descriptor(
+        name='NestedMessage',
+        full_name='protobuf_unittest.TestAllTypes.NestedMessage',
+        filename=None,
+        file=self.my_file,
+        containing_type=None,
+        fields=[
+          descriptor.FieldDescriptor(
+            name='bb',
+            full_name='protobuf_unittest.TestAllTypes.NestedMessage.bb',
+            index=0, number=1,
+            type=5, cpp_type=1, label=1,
+            has_default_value=False, default_value=0,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None),
+        ],
+        nested_types=[],
+        enum_types=[
+          self.my_enum,
+        ],
+        extensions=[])
+    self.my_method = descriptor.MethodDescriptor(
+        name='Bar',
+        full_name='protobuf_unittest.TestService.Bar',
+        index=0,
+        containing_service=None,
+        input_type=None,
+        output_type=None)
+    self.my_service = descriptor.ServiceDescriptor(
+        name='TestServiceWithOptions',
+        full_name='protobuf_unittest.TestServiceWithOptions',
+        file=self.my_file,
+        index=0,
+        methods=[
+            self.my_method
+        ])
+
+  def testEnumValueName(self):
+    self.assertEqual(self.my_message.EnumValueName('ForeignEnum', 4),
+                     'FOREIGN_FOO')
+
+    self.assertEqual(
+        self.my_message.enum_types_by_name[
+            'ForeignEnum'].values_by_number[4].name,
+        self.my_message.EnumValueName('ForeignEnum', 4))
+
+  def testEnumFixups(self):
+    self.assertEqual(self.my_enum, self.my_enum.values[0].type)
+
+  def testContainingTypeFixups(self):
+    self.assertEqual(self.my_message, self.my_message.fields[0].containing_type)
+    self.assertEqual(self.my_message, self.my_enum.containing_type)
+
+  def testContainingServiceFixups(self):
+    self.assertEqual(self.my_service, self.my_method.containing_service)
+
+  def testGetOptions(self):
+    self.assertEqual(self.my_enum.GetOptions(),
+                     descriptor_pb2.EnumOptions())
+    self.assertEqual(self.my_enum.values[0].GetOptions(),
+                     descriptor_pb2.EnumValueOptions())
+    self.assertEqual(self.my_message.GetOptions(),
+                     descriptor_pb2.MessageOptions())
+    self.assertEqual(self.my_message.fields[0].GetOptions(),
+                     descriptor_pb2.FieldOptions())
+    self.assertEqual(self.my_method.GetOptions(),
+                     descriptor_pb2.MethodOptions())
+    self.assertEqual(self.my_service.GetOptions(),
+                     descriptor_pb2.ServiceOptions())
+
+  def testSimpleCustomOptions(self):
+    file_descriptor = unittest_custom_options_pb2.DESCRIPTOR
+    message_descriptor =\
+        unittest_custom_options_pb2.TestMessageWithCustomOptions.DESCRIPTOR
+    field_descriptor = message_descriptor.fields_by_name["field1"]
+    enum_descriptor = message_descriptor.enum_types_by_name["AnEnum"]
+    enum_value_descriptor =\
+        message_descriptor.enum_values_by_name["ANENUM_VAL2"]
+    service_descriptor =\
+        unittest_custom_options_pb2.TestServiceWithCustomOptions.DESCRIPTOR
+    method_descriptor = service_descriptor.FindMethodByName("Foo")
+
+    file_options = file_descriptor.GetOptions()
+    file_opt1 = unittest_custom_options_pb2.file_opt1
+    self.assertEqual(9876543210, file_options.Extensions[file_opt1])
+    message_options = message_descriptor.GetOptions()
+    message_opt1 = unittest_custom_options_pb2.message_opt1
+    self.assertEqual(-56, message_options.Extensions[message_opt1])
+    field_options = field_descriptor.GetOptions()
+    field_opt1 = unittest_custom_options_pb2.field_opt1
+    self.assertEqual(8765432109, field_options.Extensions[field_opt1])
+    field_opt2 = unittest_custom_options_pb2.field_opt2
+    self.assertEqual(42, field_options.Extensions[field_opt2])
+    enum_options = enum_descriptor.GetOptions()
+    enum_opt1 = unittest_custom_options_pb2.enum_opt1
+    self.assertEqual(-789, enum_options.Extensions[enum_opt1])
+    enum_value_options = enum_value_descriptor.GetOptions()
+    enum_value_opt1 = unittest_custom_options_pb2.enum_value_opt1
+    self.assertEqual(123, enum_value_options.Extensions[enum_value_opt1])
+
+    service_options = service_descriptor.GetOptions()
+    service_opt1 = unittest_custom_options_pb2.service_opt1
+    self.assertEqual(-9876543210, service_options.Extensions[service_opt1])
+    method_options = method_descriptor.GetOptions()
+    method_opt1 = unittest_custom_options_pb2.method_opt1
+    self.assertEqual(unittest_custom_options_pb2.METHODOPT1_VAL2,
+                     method_options.Extensions[method_opt1])
+
+  def testDifferentCustomOptionTypes(self):
+    kint32min = -2**31
+    kint64min = -2**63
+    kint32max = 2**31 - 1
+    kint64max = 2**63 - 1
+    kuint32max = 2**32 - 1
+    kuint64max = 2**64 - 1
+
+    message_descriptor =\
+        unittest_custom_options_pb2.CustomOptionMinIntegerValues.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertEqual(False, message_options.Extensions[
+        unittest_custom_options_pb2.bool_opt])
+    self.assertEqual(kint32min, message_options.Extensions[
+        unittest_custom_options_pb2.int32_opt])
+    self.assertEqual(kint64min, message_options.Extensions[
+        unittest_custom_options_pb2.int64_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.uint32_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.uint64_opt])
+    self.assertEqual(kint32min, message_options.Extensions[
+        unittest_custom_options_pb2.sint32_opt])
+    self.assertEqual(kint64min, message_options.Extensions[
+        unittest_custom_options_pb2.sint64_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.fixed32_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.fixed64_opt])
+    self.assertEqual(kint32min, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed32_opt])
+    self.assertEqual(kint64min, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed64_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.CustomOptionMaxIntegerValues.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertEqual(True, message_options.Extensions[
+        unittest_custom_options_pb2.bool_opt])
+    self.assertEqual(kint32max, message_options.Extensions[
+        unittest_custom_options_pb2.int32_opt])
+    self.assertEqual(kint64max, message_options.Extensions[
+        unittest_custom_options_pb2.int64_opt])
+    self.assertEqual(kuint32max, message_options.Extensions[
+        unittest_custom_options_pb2.uint32_opt])
+    self.assertEqual(kuint64max, message_options.Extensions[
+        unittest_custom_options_pb2.uint64_opt])
+    self.assertEqual(kint32max, message_options.Extensions[
+        unittest_custom_options_pb2.sint32_opt])
+    self.assertEqual(kint64max, message_options.Extensions[
+        unittest_custom_options_pb2.sint64_opt])
+    self.assertEqual(kuint32max, message_options.Extensions[
+        unittest_custom_options_pb2.fixed32_opt])
+    self.assertEqual(kuint64max, message_options.Extensions[
+        unittest_custom_options_pb2.fixed64_opt])
+    self.assertEqual(kint32max, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed32_opt])
+    self.assertEqual(kint64max, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed64_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.CustomOptionOtherValues.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertEqual(-100, message_options.Extensions[
+        unittest_custom_options_pb2.int32_opt])
+    self.assertAlmostEqual(12.3456789, message_options.Extensions[
+        unittest_custom_options_pb2.float_opt], 6)
+    self.assertAlmostEqual(1.234567890123456789, message_options.Extensions[
+        unittest_custom_options_pb2.double_opt])
+    self.assertEqual("Hello, \"World\"", message_options.Extensions[
+        unittest_custom_options_pb2.string_opt])
+    self.assertEqual("Hello\0World", message_options.Extensions[
+        unittest_custom_options_pb2.bytes_opt])
+    dummy_enum = unittest_custom_options_pb2.DummyMessageContainingEnum
+    self.assertEqual(
+        dummy_enum.TEST_OPTION_ENUM_TYPE2,
+        message_options.Extensions[unittest_custom_options_pb2.enum_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.SettingRealsFromPositiveInts.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertAlmostEqual(12, message_options.Extensions[
+        unittest_custom_options_pb2.float_opt], 6)
+    self.assertAlmostEqual(154, message_options.Extensions[
+        unittest_custom_options_pb2.double_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.SettingRealsFromNegativeInts.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertAlmostEqual(-12, message_options.Extensions[
+        unittest_custom_options_pb2.float_opt], 6)
+    self.assertAlmostEqual(-154, message_options.Extensions[
+        unittest_custom_options_pb2.double_opt])
+
+  def testComplexExtensionOptions(self):
+    descriptor =\
+        unittest_custom_options_pb2.VariousComplexOptions.DESCRIPTOR
+    options = descriptor.GetOptions()
+    self.assertEqual(42, options.Extensions[
+        unittest_custom_options_pb2.complex_opt1].foo)
+    self.assertEqual(324, options.Extensions[
+        unittest_custom_options_pb2.complex_opt1].Extensions[
+            unittest_custom_options_pb2.quux])
+    self.assertEqual(876, options.Extensions[
+        unittest_custom_options_pb2.complex_opt1].Extensions[
+            unittest_custom_options_pb2.corge].qux)
+    self.assertEqual(987, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].baz)
+    self.assertEqual(654, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.grault])
+    self.assertEqual(743, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].bar.foo)
+    self.assertEqual(1999, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].bar.Extensions[
+            unittest_custom_options_pb2.quux])
+    self.assertEqual(2008, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].bar.Extensions[
+            unittest_custom_options_pb2.corge].qux)
+    self.assertEqual(741, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.garply].foo)
+    self.assertEqual(1998, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.garply].Extensions[
+                unittest_custom_options_pb2.quux])
+    self.assertEqual(2121, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.garply].Extensions[
+                unittest_custom_options_pb2.corge].qux)
+    self.assertEqual(1971, options.Extensions[
+        unittest_custom_options_pb2.ComplexOptionType2
+        .ComplexOptionType4.complex_opt4].waldo)
+    self.assertEqual(321, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].fred.waldo)
+    self.assertEqual(9, options.Extensions[
+        unittest_custom_options_pb2.complex_opt3].qux)
+    self.assertEqual(22, options.Extensions[
+        unittest_custom_options_pb2.complex_opt3].complexoptiontype5.plugh)
+    self.assertEqual(24, options.Extensions[
+        unittest_custom_options_pb2.complexopt6].xyzzy)
+
+  # Check that aggregate options were parsed and saved correctly in
+  # the appropriate descriptors.
+  def testAggregateOptions(self):
+    file_descriptor = unittest_custom_options_pb2.DESCRIPTOR
+    message_descriptor =\
+        unittest_custom_options_pb2.AggregateMessage.DESCRIPTOR
+    field_descriptor = message_descriptor.fields_by_name["fieldname"]
+    enum_descriptor = unittest_custom_options_pb2.AggregateEnum.DESCRIPTOR
+    enum_value_descriptor = enum_descriptor.values_by_name["VALUE"]
+    service_descriptor =\
+        unittest_custom_options_pb2.AggregateService.DESCRIPTOR
+    method_descriptor = service_descriptor.FindMethodByName("Method")
+
+    # Tests for the different types of data embedded in fileopt
+    file_options = file_descriptor.GetOptions().Extensions[
+        unittest_custom_options_pb2.fileopt]
+    self.assertEqual(100, file_options.i)
+    self.assertEqual("FileAnnotation", file_options.s)
+    self.assertEqual("NestedFileAnnotation", file_options.sub.s)
+    self.assertEqual("FileExtensionAnnotation", file_options.file.Extensions[
+        unittest_custom_options_pb2.fileopt].s)
+    self.assertEqual("EmbeddedMessageSetElement", file_options.mset.Extensions[
+        unittest_custom_options_pb2.AggregateMessageSetElement
+        .message_set_extension].s)
+
+    # Simple tests for all the other types of annotations
+    self.assertEqual(
+        "MessageAnnotation",
+        message_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.msgopt].s)
+    self.assertEqual(
+        "FieldAnnotation",
+        field_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.fieldopt].s)
+    self.assertEqual(
+        "EnumAnnotation",
+        enum_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.enumopt].s)
+    self.assertEqual(
+        "EnumValueAnnotation",
+        enum_value_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.enumvalopt].s)
+    self.assertEqual(
+        "ServiceAnnotation",
+        service_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.serviceopt].s)
+    self.assertEqual(
+        "MethodAnnotation",
+        method_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.methodopt].s)
+
+  def testNestedOptions(self):
+    nested_message =\
+        unittest_custom_options_pb2.NestedOptionType.NestedMessage.DESCRIPTOR
+    self.assertEqual(1001, nested_message.GetOptions().Extensions[
+        unittest_custom_options_pb2.message_opt1])
+    nested_field = nested_message.fields_by_name["nested_field"]
+    self.assertEqual(1002, nested_field.GetOptions().Extensions[
+        unittest_custom_options_pb2.field_opt1])
+    outer_message =\
+        unittest_custom_options_pb2.NestedOptionType.DESCRIPTOR
+    nested_enum = outer_message.enum_types_by_name["NestedEnum"]
+    self.assertEqual(1003, nested_enum.GetOptions().Extensions[
+        unittest_custom_options_pb2.enum_opt1])
+    nested_enum_value = outer_message.enum_values_by_name["NESTED_ENUM_VALUE"]
+    self.assertEqual(1004, nested_enum_value.GetOptions().Extensions[
+        unittest_custom_options_pb2.enum_value_opt1])
+    nested_extension = outer_message.extensions_by_name["nested_extension"]
+    self.assertEqual(1005, nested_extension.GetOptions().Extensions[
+        unittest_custom_options_pb2.field_opt2])
+
+  def testFileDescriptorReferences(self):
+    self.assertEqual(self.my_enum.file, self.my_file)
+    self.assertEqual(self.my_message.file, self.my_file)
+
+  def testFileDescriptor(self):
+    self.assertEqual(self.my_file.name, 'some/filename/some.proto')
+    self.assertEqual(self.my_file.package, 'protobuf_unittest')
+
+
+class DescriptorCopyToProtoTest(unittest.TestCase):
+  """Tests for CopyTo functions of Descriptor."""
+
+  def _AssertProtoEqual(self, actual_proto, expected_class, expected_ascii):
+    expected_proto = expected_class()
+    text_format.Merge(expected_ascii, expected_proto)
+
+    self.assertEqual(
+        actual_proto, expected_proto,
+        'Not equal,\nActual:\n%s\nExpected:\n%s\n'
+        % (str(actual_proto), str(expected_proto)))
+
+  def _InternalTestCopyToProto(self, desc, expected_proto_class,
+                               expected_proto_ascii):
+    actual = expected_proto_class()
+    desc.CopyToProto(actual)
+    self._AssertProtoEqual(
+        actual, expected_proto_class, expected_proto_ascii)
+
+  def testCopyToProto_EmptyMessage(self):
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestEmptyMessage.DESCRIPTOR,
+        descriptor_pb2.DescriptorProto,
+        TEST_EMPTY_MESSAGE_DESCRIPTOR_ASCII)
+
+  def testCopyToProto_NestedMessage(self):
+    TEST_NESTED_MESSAGE_ASCII = """
+      name: 'NestedMessage'
+      field: <
+        name: 'bb'
+        number: 1
+        label: 1  # Optional
+        type: 5  # TYPE_INT32
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestAllTypes.NestedMessage.DESCRIPTOR,
+        descriptor_pb2.DescriptorProto,
+        TEST_NESTED_MESSAGE_ASCII)
+
+  def testCopyToProto_ForeignNestedMessage(self):
+    TEST_FOREIGN_NESTED_ASCII = """
+      name: 'TestForeignNested'
+      field: <
+        name: 'foreign_nested'
+        number: 1
+        label: 1  # Optional
+        type: 11  # TYPE_MESSAGE
+        type_name: '.protobuf_unittest.TestAllTypes.NestedMessage'
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestForeignNested.DESCRIPTOR,
+        descriptor_pb2.DescriptorProto,
+        TEST_FOREIGN_NESTED_ASCII)
+
+  def testCopyToProto_ForeignEnum(self):
+    TEST_FOREIGN_ENUM_ASCII = """
+      name: 'ForeignEnum'
+      value: <
+        name: 'FOREIGN_FOO'
+        number: 4
+      >
+      value: <
+        name: 'FOREIGN_BAR'
+        number: 5
+      >
+      value: <
+        name: 'FOREIGN_BAZ'
+        number: 6
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2._FOREIGNENUM,
+        descriptor_pb2.EnumDescriptorProto,
+        TEST_FOREIGN_ENUM_ASCII)
+
+  def testCopyToProto_Options(self):
+    TEST_DEPRECATED_FIELDS_ASCII = """
+      name: 'TestDeprecatedFields'
+      field: <
+        name: 'deprecated_int32'
+        number: 1
+        label: 1  # Optional
+        type: 5  # TYPE_INT32
+        options: <
+          deprecated: true
+        >
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestDeprecatedFields.DESCRIPTOR,
+        descriptor_pb2.DescriptorProto,
+        TEST_DEPRECATED_FIELDS_ASCII)
+
+  def testCopyToProto_AllExtensions(self):
+    TEST_EMPTY_MESSAGE_WITH_EXTENSIONS_ASCII = """
+      name: 'TestEmptyMessageWithExtensions'
+      extension_range: <
+        start: 1
+        end: 536870912
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestEmptyMessageWithExtensions.DESCRIPTOR,
+        descriptor_pb2.DescriptorProto,
+        TEST_EMPTY_MESSAGE_WITH_EXTENSIONS_ASCII)
+
+  def testCopyToProto_SeveralExtensions(self):
+    TEST_MESSAGE_WITH_SEVERAL_EXTENSIONS_ASCII = """
+      name: 'TestMultipleExtensionRanges'
+      extension_range: <
+        start: 42
+        end: 43
+      >
+      extension_range: <
+        start: 4143
+        end: 4244
+      >
+      extension_range: <
+        start: 65536
+        end: 536870912
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestMultipleExtensionRanges.DESCRIPTOR,
+        descriptor_pb2.DescriptorProto,
+        TEST_MESSAGE_WITH_SEVERAL_EXTENSIONS_ASCII)
+
+  def testCopyToProto_FileDescriptor(self):
+    UNITTEST_IMPORT_FILE_DESCRIPTOR_ASCII = ("""
+      name: 'google/protobuf/unittest_import.proto'
+      package: 'protobuf_unittest_import'
+      dependency: 'google/protobuf/unittest_import_public.proto'
+      message_type: <
+        name: 'ImportMessage'
+        field: <
+          name: 'd'
+          number: 1
+          label: 1  # Optional
+          type: 5  # TYPE_INT32
+        >
+      >
+      """ +
+      """enum_type: <
+        name: 'ImportEnum'
+        value: <
+          name: 'IMPORT_FOO'
+          number: 7
+        >
+        value: <
+          name: 'IMPORT_BAR'
+          number: 8
+        >
+        value: <
+          name: 'IMPORT_BAZ'
+          number: 9
+        >
+      >
+      options: <
+        java_package: 'com.google.protobuf.test'
+        optimize_for: 1  # SPEED
+      >
+      public_dependency: 0
+      """)
+
+    self._InternalTestCopyToProto(
+        unittest_import_pb2.DESCRIPTOR,
+        descriptor_pb2.FileDescriptorProto,
+        UNITTEST_IMPORT_FILE_DESCRIPTOR_ASCII)
+
+  def testCopyToProto_ServiceDescriptor(self):
+    TEST_SERVICE_ASCII = """
+      name: 'TestService'
+      method: <
+        name: 'Foo'
+        input_type: '.protobuf_unittest.FooRequest'
+        output_type: '.protobuf_unittest.FooResponse'
+      >
+      method: <
+        name: 'Bar'
+        input_type: '.protobuf_unittest.BarRequest'
+        output_type: '.protobuf_unittest.BarResponse'
+      >
+      """
+
+    self._InternalTestCopyToProto(
+        unittest_pb2.TestService.DESCRIPTOR,
+        descriptor_pb2.ServiceDescriptorProto,
+        TEST_SERVICE_ASCII)
+
+
+class MakeDescriptorTest(unittest.TestCase):
+  def testMakeDescriptorWithUnsignedIntField(self):
+    file_descriptor_proto = descriptor_pb2.FileDescriptorProto()
+    file_descriptor_proto.name = 'Foo'
+    message_type = file_descriptor_proto.message_type.add()
+    message_type.name = file_descriptor_proto.name
+    field = message_type.field.add()
+    field.number = 1
+    field.name = 'uint64_field'
+    field.label = descriptor.FieldDescriptor.LABEL_REQUIRED
+    field.type = descriptor.FieldDescriptor.TYPE_UINT64
+    result = descriptor.MakeDescriptor(message_type)
+    self.assertEqual(result.fields[0].cpp_type,
+                     descriptor.FieldDescriptor.CPPTYPE_UINT64)
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/generator_test.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/generator_test.py
new file mode 100755
index 0000000..8343aba
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/generator_test.py
@@ -0,0 +1,269 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# TODO(robinson): Flesh this out considerably.  We focused on reflection_test.py
+# first, since it's testing the subtler code, and since it provides decent
+# indirect testing of the protocol compiler output.
+
+"""Unittest that directly tests the output of the pure-Python protocol
+compiler.  See //google/protobuf/reflection_test.py for a test which
+further ensures that we can use Python protocol message objects as we expect.
+"""
+
+__author__ = 'robinson@google.com (Will Robinson)'
+
+import unittest
+from google.protobuf.internal import test_bad_identifiers_pb2
+from google.protobuf import unittest_custom_options_pb2
+from google.protobuf import unittest_import_pb2
+from google.protobuf import unittest_import_public_pb2
+from google.protobuf import unittest_mset_pb2
+from google.protobuf import unittest_pb2
+from google.protobuf import unittest_no_generic_services_pb2
+from google.protobuf import service
+
+MAX_EXTENSION = 536870912
+
+
+class GeneratorTest(unittest.TestCase):
+
+  def testNestedMessageDescriptor(self):
+    field_name = 'optional_nested_message'
+    proto_type = unittest_pb2.TestAllTypes
+    self.assertEqual(
+        proto_type.NestedMessage.DESCRIPTOR,
+        proto_type.DESCRIPTOR.fields_by_name[field_name].message_type)
+
+  def testEnums(self):
+    # We test only module-level enums here.
+    # TODO(robinson): Examine descriptors directly to check
+    # enum descriptor output.
+    self.assertEqual(4, unittest_pb2.FOREIGN_FOO)
+    self.assertEqual(5, unittest_pb2.FOREIGN_BAR)
+    self.assertEqual(6, unittest_pb2.FOREIGN_BAZ)
+
+    proto = unittest_pb2.TestAllTypes()
+    self.assertEqual(1, proto.FOO)
+    self.assertEqual(1, unittest_pb2.TestAllTypes.FOO)
+    self.assertEqual(2, proto.BAR)
+    self.assertEqual(2, unittest_pb2.TestAllTypes.BAR)
+    self.assertEqual(3, proto.BAZ)
+    self.assertEqual(3, unittest_pb2.TestAllTypes.BAZ)
+
+  def testExtremeDefaultValues(self):
+    message = unittest_pb2.TestExtremeDefaultValues()
+
+    # Python pre-2.6 does not have isinf() or isnan() functions, so we have
+    # to provide our own.
+    def isnan(val):
+      # NaN is never equal to itself.
+      return val != val
+    def isinf(val):
+      # Infinity times zero equals NaN.
+      return not isnan(val) and isnan(val * 0)
+
+    self.assertTrue(isinf(message.inf_double))
+    self.assertTrue(message.inf_double > 0)
+    self.assertTrue(isinf(message.neg_inf_double))
+    self.assertTrue(message.neg_inf_double < 0)
+    self.assertTrue(isnan(message.nan_double))
+
+    self.assertTrue(isinf(message.inf_float))
+    self.assertTrue(message.inf_float > 0)
+    self.assertTrue(isinf(message.neg_inf_float))
+    self.assertTrue(message.neg_inf_float < 0)
+    self.assertTrue(isnan(message.nan_float))
+    self.assertEqual("? ? ?? ?? ??? ??/ ??-", message.cpp_trigraph)
+
+  def testHasDefaultValues(self):
+    desc = unittest_pb2.TestAllTypes.DESCRIPTOR
+
+    expected_has_default_by_name = {
+        'optional_int32': False,
+        'repeated_int32': False,
+        'optional_nested_message': False,
+        'default_int32': True,
+    }
+
+    has_default_by_name = dict(
+        [(f.name, f.has_default_value)
+         for f in desc.fields
+         if f.name in expected_has_default_by_name])
+    self.assertEqual(expected_has_default_by_name, has_default_by_name)
+
+  def testContainingTypeBehaviorForExtensions(self):
+    self.assertEqual(unittest_pb2.optional_int32_extension.containing_type,
+                     unittest_pb2.TestAllExtensions.DESCRIPTOR)
+    self.assertEqual(unittest_pb2.TestRequired.single.containing_type,
+                     unittest_pb2.TestAllExtensions.DESCRIPTOR)
+
+  def testExtensionScope(self):
+    self.assertEqual(unittest_pb2.optional_int32_extension.extension_scope,
+                     None)
+    self.assertEqual(unittest_pb2.TestRequired.single.extension_scope,
+                     unittest_pb2.TestRequired.DESCRIPTOR)
+
+  def testIsExtension(self):
+    self.assertTrue(unittest_pb2.optional_int32_extension.is_extension)
+    self.assertTrue(unittest_pb2.TestRequired.single.is_extension)
+
+    message_descriptor = unittest_pb2.TestRequired.DESCRIPTOR
+    non_extension_descriptor = message_descriptor.fields_by_name['a']
+    self.assertTrue(not non_extension_descriptor.is_extension)
+
+  def testOptions(self):
+    proto = unittest_mset_pb2.TestMessageSet()
+    self.assertTrue(proto.DESCRIPTOR.GetOptions().message_set_wire_format)
+
+  def testMessageWithCustomOptions(self):
+    proto = unittest_custom_options_pb2.TestMessageWithCustomOptions()
+    enum_options = proto.DESCRIPTOR.enum_types_by_name['AnEnum'].GetOptions()
+    self.assertTrue(enum_options is not None)
+    # TODO(gps): We really should test for the presense of the enum_opt1
+    # extension and for its value to be set to -789.
+
+  def testNestedTypes(self):
+    self.assertEquals(
+        set(unittest_pb2.TestAllTypes.DESCRIPTOR.nested_types),
+        set([
+            unittest_pb2.TestAllTypes.NestedMessage.DESCRIPTOR,
+            unittest_pb2.TestAllTypes.OptionalGroup.DESCRIPTOR,
+            unittest_pb2.TestAllTypes.RepeatedGroup.DESCRIPTOR,
+        ]))
+    self.assertEqual(unittest_pb2.TestEmptyMessage.DESCRIPTOR.nested_types, [])
+    self.assertEqual(
+        unittest_pb2.TestAllTypes.NestedMessage.DESCRIPTOR.nested_types, [])
+
+  def testContainingType(self):
+    self.assertTrue(
+        unittest_pb2.TestEmptyMessage.DESCRIPTOR.containing_type is None)
+    self.assertTrue(
+        unittest_pb2.TestAllTypes.DESCRIPTOR.containing_type is None)
+    self.assertEqual(
+        unittest_pb2.TestAllTypes.NestedMessage.DESCRIPTOR.containing_type,
+        unittest_pb2.TestAllTypes.DESCRIPTOR)
+    self.assertEqual(
+        unittest_pb2.TestAllTypes.NestedMessage.DESCRIPTOR.containing_type,
+        unittest_pb2.TestAllTypes.DESCRIPTOR)
+    self.assertEqual(
+        unittest_pb2.TestAllTypes.RepeatedGroup.DESCRIPTOR.containing_type,
+        unittest_pb2.TestAllTypes.DESCRIPTOR)
+
+  def testContainingTypeInEnumDescriptor(self):
+    self.assertTrue(unittest_pb2._FOREIGNENUM.containing_type is None)
+    self.assertEqual(unittest_pb2._TESTALLTYPES_NESTEDENUM.containing_type,
+                     unittest_pb2.TestAllTypes.DESCRIPTOR)
+
+  def testPackage(self):
+    self.assertEqual(
+        unittest_pb2.TestAllTypes.DESCRIPTOR.file.package,
+        'protobuf_unittest')
+    desc = unittest_pb2.TestAllTypes.NestedMessage.DESCRIPTOR
+    self.assertEqual(desc.file.package, 'protobuf_unittest')
+    self.assertEqual(
+        unittest_import_pb2.ImportMessage.DESCRIPTOR.file.package,
+        'protobuf_unittest_import')
+
+    self.assertEqual(
+        unittest_pb2._FOREIGNENUM.file.package, 'protobuf_unittest')
+    self.assertEqual(
+        unittest_pb2._TESTALLTYPES_NESTEDENUM.file.package,
+        'protobuf_unittest')
+    self.assertEqual(
+        unittest_import_pb2._IMPORTENUM.file.package,
+        'protobuf_unittest_import')
+
+  def testExtensionRange(self):
+    self.assertEqual(
+        unittest_pb2.TestAllTypes.DESCRIPTOR.extension_ranges, [])
+    self.assertEqual(
+        unittest_pb2.TestAllExtensions.DESCRIPTOR.extension_ranges,
+        [(1, MAX_EXTENSION)])
+    self.assertEqual(
+        unittest_pb2.TestMultipleExtensionRanges.DESCRIPTOR.extension_ranges,
+        [(42, 43), (4143, 4244), (65536, MAX_EXTENSION)])
+
+  def testFileDescriptor(self):
+    self.assertEqual(unittest_pb2.DESCRIPTOR.name,
+                     'google/protobuf/unittest.proto')
+    self.assertEqual(unittest_pb2.DESCRIPTOR.package, 'protobuf_unittest')
+    self.assertFalse(unittest_pb2.DESCRIPTOR.serialized_pb is None)
+
+  def testNoGenericServices(self):
+    self.assertTrue(hasattr(unittest_no_generic_services_pb2, "TestMessage"))
+    self.assertTrue(hasattr(unittest_no_generic_services_pb2, "FOO"))
+    self.assertTrue(hasattr(unittest_no_generic_services_pb2, "test_extension"))
+
+    # Make sure unittest_no_generic_services_pb2 has no services subclassing
+    # Proto2 Service class.
+    if hasattr(unittest_no_generic_services_pb2, "TestService"):
+      self.assertFalse(issubclass(unittest_no_generic_services_pb2.TestService,
+                                  service.Service))
+
+  def testMessageTypesByName(self):
+    file_type = unittest_pb2.DESCRIPTOR
+    self.assertEqual(
+        unittest_pb2._TESTALLTYPES,
+        file_type.message_types_by_name[unittest_pb2._TESTALLTYPES.name])
+
+    # Nested messages shouldn't be included in the message_types_by_name
+    # dictionary (like in the C++ API).
+    self.assertFalse(
+        unittest_pb2._TESTALLTYPES_NESTEDMESSAGE.name in
+        file_type.message_types_by_name)
+
+  def testPublicImports(self):
+    # Test public imports as embedded message.
+    all_type_proto = unittest_pb2.TestAllTypes()
+    self.assertEqual(0, all_type_proto.optional_public_import_message.e)
+
+    # PublicImportMessage is actually defined in unittest_import_public_pb2
+    # module, and is public imported by unittest_import_pb2 module.
+    public_import_proto = unittest_import_pb2.PublicImportMessage()
+    self.assertEqual(0, public_import_proto.e)
+    self.assertTrue(unittest_import_public_pb2.PublicImportMessage is
+                    unittest_import_pb2.PublicImportMessage)
+
+  def testBadIdentifiers(self):
+    # We're just testing that the code was imported without problems.
+    message = test_bad_identifiers_pb2.TestBadIdentifiers()
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.message],
+                     "foo")
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.descriptor],
+                     "bar")
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.reflection],
+                     "baz")
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.service],
+                     "qux")
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/golden_message b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/golden_message
new file mode 100644
index 0000000..4dd62cd
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/golden_message
Binary files differ
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/golden_packed_fields_message b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/golden_packed_fields_message
new file mode 100644
index 0000000..ee28d38
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/golden_packed_fields_message
Binary files differ
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/message_test.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/message_test.py
new file mode 100755
index 0000000..e71b295
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/message_test.py
@@ -0,0 +1,499 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests python protocol buffers against the golden message.
+
+Note that the golden messages exercise every known field type, thus this
+test ends up exercising and verifying nearly all of the parsing and
+serialization code in the whole library.
+
+TODO(kenton):  Merge with wire_format_test?  It doesn't make a whole lot of
+sense to call this a test of the "message" module, which only declares an
+abstract interface.
+"""
+
+__author__ = 'gps@google.com (Gregory P. Smith)'
+
+import copy
+import math
+import operator
+import pickle
+
+import unittest
+from google.protobuf import unittest_import_pb2
+from google.protobuf import unittest_pb2
+from google.protobuf.internal import api_implementation
+from google.protobuf.internal import test_util
+from google.protobuf import message
+
+try:
+  cmp                                   # Python 2
+except NameError:
+  cmp = lambda x, y: (x > y) - (x < y)  # Python 3
+
+# Python pre-2.6 does not have isinf() or isnan() functions, so we have
+# to provide our own.
+def isnan(val):
+  # NaN is never equal to itself.
+  return val != val
+def isinf(val):
+  # Infinity times zero equals NaN.
+  return not isnan(val) and isnan(val * 0)
+def IsPosInf(val):
+  return isinf(val) and (val > 0)
+def IsNegInf(val):
+  return isinf(val) and (val < 0)
+
+class MessageTest(unittest.TestCase):
+
+  def testGoldenMessage(self):
+    golden_data = test_util.GoldenFile('golden_message').read()
+    golden_message = unittest_pb2.TestAllTypes()
+    golden_message.ParseFromString(golden_data)
+    test_util.ExpectAllFieldsSet(self, golden_message)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
+    golden_copy = copy.deepcopy(golden_message)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
+
+  def testGoldenExtensions(self):
+    golden_data = test_util.GoldenFile('golden_message').read()
+    golden_message = unittest_pb2.TestAllExtensions()
+    golden_message.ParseFromString(golden_data)
+    all_set = unittest_pb2.TestAllExtensions()
+    test_util.SetAllExtensions(all_set)
+    self.assertEquals(all_set, golden_message)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
+    golden_copy = copy.deepcopy(golden_message)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
+
+  def testGoldenPackedMessage(self):
+    golden_data = test_util.GoldenFile('golden_packed_fields_message').read()
+    golden_message = unittest_pb2.TestPackedTypes()
+    golden_message.ParseFromString(golden_data)
+    all_set = unittest_pb2.TestPackedTypes()
+    test_util.SetAllPackedFields(all_set)
+    self.assertEquals(all_set, golden_message)
+    self.assertEqual(golden_data, all_set.SerializeToString())
+    golden_copy = copy.deepcopy(golden_message)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
+
+  def testGoldenPackedExtensions(self):
+    golden_data = test_util.GoldenFile('golden_packed_fields_message').read()
+    golden_message = unittest_pb2.TestPackedExtensions()
+    golden_message.ParseFromString(golden_data)
+    all_set = unittest_pb2.TestPackedExtensions()
+    test_util.SetAllPackedExtensions(all_set)
+    self.assertEquals(all_set, golden_message)
+    self.assertEqual(golden_data, all_set.SerializeToString())
+    golden_copy = copy.deepcopy(golden_message)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
+
+  def testPickleSupport(self):
+    golden_data = test_util.GoldenFile('golden_message').read()
+    golden_message = unittest_pb2.TestAllTypes()
+    golden_message.ParseFromString(golden_data)
+    pickled_message = pickle.dumps(golden_message)
+
+    unpickled_message = pickle.loads(pickled_message)
+    self.assertEquals(unpickled_message, golden_message)
+
+  def testPickleIncompleteProto(self):
+    golden_message = unittest_pb2.TestRequired(a=1)
+    pickled_message = pickle.dumps(golden_message)
+
+    unpickled_message = pickle.loads(pickled_message)
+    self.assertEquals(unpickled_message, golden_message)
+    self.assertEquals(unpickled_message.a, 1)
+    # This is still an incomplete proto - so serializing should fail
+    self.assertRaises(message.EncodeError, unpickled_message.SerializeToString)
+
+  def testPositiveInfinity(self):
+    golden_data = ('\x5D\x00\x00\x80\x7F'
+                   '\x61\x00\x00\x00\x00\x00\x00\xF0\x7F'
+                   '\xCD\x02\x00\x00\x80\x7F'
+                   '\xD1\x02\x00\x00\x00\x00\x00\x00\xF0\x7F')
+    golden_message = unittest_pb2.TestAllTypes()
+    golden_message.ParseFromString(golden_data)
+    self.assertTrue(IsPosInf(golden_message.optional_float))
+    self.assertTrue(IsPosInf(golden_message.optional_double))
+    self.assertTrue(IsPosInf(golden_message.repeated_float[0]))
+    self.assertTrue(IsPosInf(golden_message.repeated_double[0]))
+    self.assertEqual(golden_data, golden_message.SerializeToString())
+
+  def testNegativeInfinity(self):
+    golden_data = ('\x5D\x00\x00\x80\xFF'
+                   '\x61\x00\x00\x00\x00\x00\x00\xF0\xFF'
+                   '\xCD\x02\x00\x00\x80\xFF'
+                   '\xD1\x02\x00\x00\x00\x00\x00\x00\xF0\xFF')
+    golden_message = unittest_pb2.TestAllTypes()
+    golden_message.ParseFromString(golden_data)
+    self.assertTrue(IsNegInf(golden_message.optional_float))
+    self.assertTrue(IsNegInf(golden_message.optional_double))
+    self.assertTrue(IsNegInf(golden_message.repeated_float[0]))
+    self.assertTrue(IsNegInf(golden_message.repeated_double[0]))
+    self.assertEqual(golden_data, golden_message.SerializeToString())
+
+  def testNotANumber(self):
+    golden_data = ('\x5D\x00\x00\xC0\x7F'
+                   '\x61\x00\x00\x00\x00\x00\x00\xF8\x7F'
+                   '\xCD\x02\x00\x00\xC0\x7F'
+                   '\xD1\x02\x00\x00\x00\x00\x00\x00\xF8\x7F')
+    golden_message = unittest_pb2.TestAllTypes()
+    golden_message.ParseFromString(golden_data)
+    self.assertTrue(isnan(golden_message.optional_float))
+    self.assertTrue(isnan(golden_message.optional_double))
+    self.assertTrue(isnan(golden_message.repeated_float[0]))
+    self.assertTrue(isnan(golden_message.repeated_double[0]))
+
+    # The protocol buffer may serialize to any one of multiple different
+    # representations of a NaN.  Rather than verify a specific representation,
+    # verify the serialized string can be converted into a correctly
+    # behaving protocol buffer.
+    serialized = golden_message.SerializeToString()
+    message = unittest_pb2.TestAllTypes()
+    message.ParseFromString(serialized)
+    self.assertTrue(isnan(message.optional_float))
+    self.assertTrue(isnan(message.optional_double))
+    self.assertTrue(isnan(message.repeated_float[0]))
+    self.assertTrue(isnan(message.repeated_double[0]))
+
+  def testPositiveInfinityPacked(self):
+    golden_data = ('\xA2\x06\x04\x00\x00\x80\x7F'
+                   '\xAA\x06\x08\x00\x00\x00\x00\x00\x00\xF0\x7F')
+    golden_message = unittest_pb2.TestPackedTypes()
+    golden_message.ParseFromString(golden_data)
+    self.assertTrue(IsPosInf(golden_message.packed_float[0]))
+    self.assertTrue(IsPosInf(golden_message.packed_double[0]))
+    self.assertEqual(golden_data, golden_message.SerializeToString())
+
+  def testNegativeInfinityPacked(self):
+    golden_data = ('\xA2\x06\x04\x00\x00\x80\xFF'
+                   '\xAA\x06\x08\x00\x00\x00\x00\x00\x00\xF0\xFF')
+    golden_message = unittest_pb2.TestPackedTypes()
+    golden_message.ParseFromString(golden_data)
+    self.assertTrue(IsNegInf(golden_message.packed_float[0]))
+    self.assertTrue(IsNegInf(golden_message.packed_double[0]))
+    self.assertEqual(golden_data, golden_message.SerializeToString())
+
+  def testNotANumberPacked(self):
+    golden_data = ('\xA2\x06\x04\x00\x00\xC0\x7F'
+                   '\xAA\x06\x08\x00\x00\x00\x00\x00\x00\xF8\x7F')
+    golden_message = unittest_pb2.TestPackedTypes()
+    golden_message.ParseFromString(golden_data)
+    self.assertTrue(isnan(golden_message.packed_float[0]))
+    self.assertTrue(isnan(golden_message.packed_double[0]))
+
+    serialized = golden_message.SerializeToString()
+    message = unittest_pb2.TestPackedTypes()
+    message.ParseFromString(serialized)
+    self.assertTrue(isnan(message.packed_float[0]))
+    self.assertTrue(isnan(message.packed_double[0]))
+
+  def testExtremeFloatValues(self):
+    message = unittest_pb2.TestAllTypes()
+
+    # Most positive exponent, no significand bits set.
+    kMostPosExponentNoSigBits = math.pow(2, 127)
+    message.optional_float = kMostPosExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == kMostPosExponentNoSigBits)
+
+    # Most positive exponent, one significand bit set.
+    kMostPosExponentOneSigBit = 1.5 * math.pow(2, 127)
+    message.optional_float = kMostPosExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == kMostPosExponentOneSigBit)
+
+    # Repeat last two cases with values of same magnitude, but negative.
+    message.optional_float = -kMostPosExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == -kMostPosExponentNoSigBits)
+
+    message.optional_float = -kMostPosExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == -kMostPosExponentOneSigBit)
+
+    # Most negative exponent, no significand bits set.
+    kMostNegExponentNoSigBits = math.pow(2, -127)
+    message.optional_float = kMostNegExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == kMostNegExponentNoSigBits)
+
+    # Most negative exponent, one significand bit set.
+    kMostNegExponentOneSigBit = 1.5 * math.pow(2, -127)
+    message.optional_float = kMostNegExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == kMostNegExponentOneSigBit)
+
+    # Repeat last two cases with values of the same magnitude, but negative.
+    message.optional_float = -kMostNegExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == -kMostNegExponentNoSigBits)
+
+    message.optional_float = -kMostNegExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_float == -kMostNegExponentOneSigBit)
+
+  def testExtremeDoubleValues(self):
+    message = unittest_pb2.TestAllTypes()
+
+    # Most positive exponent, no significand bits set.
+    kMostPosExponentNoSigBits = math.pow(2, 1023)
+    message.optional_double = kMostPosExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == kMostPosExponentNoSigBits)
+
+    # Most positive exponent, one significand bit set.
+    kMostPosExponentOneSigBit = 1.5 * math.pow(2, 1023)
+    message.optional_double = kMostPosExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == kMostPosExponentOneSigBit)
+
+    # Repeat last two cases with values of same magnitude, but negative.
+    message.optional_double = -kMostPosExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == -kMostPosExponentNoSigBits)
+
+    message.optional_double = -kMostPosExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == -kMostPosExponentOneSigBit)
+
+    # Most negative exponent, no significand bits set.
+    kMostNegExponentNoSigBits = math.pow(2, -1023)
+    message.optional_double = kMostNegExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == kMostNegExponentNoSigBits)
+
+    # Most negative exponent, one significand bit set.
+    kMostNegExponentOneSigBit = 1.5 * math.pow(2, -1023)
+    message.optional_double = kMostNegExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == kMostNegExponentOneSigBit)
+
+    # Repeat last two cases with values of the same magnitude, but negative.
+    message.optional_double = -kMostNegExponentNoSigBits
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == -kMostNegExponentNoSigBits)
+
+    message.optional_double = -kMostNegExponentOneSigBit
+    message.ParseFromString(message.SerializeToString())
+    self.assertTrue(message.optional_double == -kMostNegExponentOneSigBit)
+
+  def testSortingRepeatedScalarFieldsDefaultComparator(self):
+    """Check some different types with the default comparator."""
+    message = unittest_pb2.TestAllTypes()
+
+    # TODO(mattp): would testing more scalar types strengthen test?
+    message.repeated_int32.append(1)
+    message.repeated_int32.append(3)
+    message.repeated_int32.append(2)
+    message.repeated_int32.sort()
+    self.assertEqual(message.repeated_int32[0], 1)
+    self.assertEqual(message.repeated_int32[1], 2)
+    self.assertEqual(message.repeated_int32[2], 3)
+
+    message.repeated_float.append(1.1)
+    message.repeated_float.append(1.3)
+    message.repeated_float.append(1.2)
+    message.repeated_float.sort()
+    self.assertAlmostEqual(message.repeated_float[0], 1.1)
+    self.assertAlmostEqual(message.repeated_float[1], 1.2)
+    self.assertAlmostEqual(message.repeated_float[2], 1.3)
+
+    message.repeated_string.append('a')
+    message.repeated_string.append('c')
+    message.repeated_string.append('b')
+    message.repeated_string.sort()
+    self.assertEqual(message.repeated_string[0], 'a')
+    self.assertEqual(message.repeated_string[1], 'b')
+    self.assertEqual(message.repeated_string[2], 'c')
+
+    message.repeated_bytes.append('a')
+    message.repeated_bytes.append('c')
+    message.repeated_bytes.append('b')
+    message.repeated_bytes.sort()
+    self.assertEqual(message.repeated_bytes[0], 'a')
+    self.assertEqual(message.repeated_bytes[1], 'b')
+    self.assertEqual(message.repeated_bytes[2], 'c')
+
+  def testSortingRepeatedScalarFieldsCustomComparator(self):
+    """Check some different types with custom comparator."""
+    message = unittest_pb2.TestAllTypes()
+
+    message.repeated_int32.append(-3)
+    message.repeated_int32.append(-2)
+    message.repeated_int32.append(-1)
+    message.repeated_int32.sort(lambda x,y: cmp(abs(x), abs(y)))
+    self.assertEqual(message.repeated_int32[0], -1)
+    self.assertEqual(message.repeated_int32[1], -2)
+    self.assertEqual(message.repeated_int32[2], -3)
+
+    message.repeated_string.append('aaa')
+    message.repeated_string.append('bb')
+    message.repeated_string.append('c')
+    message.repeated_string.sort(lambda x,y: cmp(len(x), len(y)))
+    self.assertEqual(message.repeated_string[0], 'c')
+    self.assertEqual(message.repeated_string[1], 'bb')
+    self.assertEqual(message.repeated_string[2], 'aaa')
+
+  def testSortingRepeatedCompositeFieldsCustomComparator(self):
+    """Check passing a custom comparator to sort a repeated composite field."""
+    message = unittest_pb2.TestAllTypes()
+
+    message.repeated_nested_message.add().bb = 1
+    message.repeated_nested_message.add().bb = 3
+    message.repeated_nested_message.add().bb = 2
+    message.repeated_nested_message.add().bb = 6
+    message.repeated_nested_message.add().bb = 5
+    message.repeated_nested_message.add().bb = 4
+    message.repeated_nested_message.sort(lambda x,y: cmp(x.bb, y.bb))
+    self.assertEqual(message.repeated_nested_message[0].bb, 1)
+    self.assertEqual(message.repeated_nested_message[1].bb, 2)
+    self.assertEqual(message.repeated_nested_message[2].bb, 3)
+    self.assertEqual(message.repeated_nested_message[3].bb, 4)
+    self.assertEqual(message.repeated_nested_message[4].bb, 5)
+    self.assertEqual(message.repeated_nested_message[5].bb, 6)
+
+  def testRepeatedCompositeFieldSortArguments(self):
+    """Check sorting a repeated composite field using list.sort() arguments."""
+    message = unittest_pb2.TestAllTypes()
+
+    get_bb = operator.attrgetter('bb')
+    cmp_bb = lambda a, b: cmp(a.bb, b.bb)
+    message.repeated_nested_message.add().bb = 1
+    message.repeated_nested_message.add().bb = 3
+    message.repeated_nested_message.add().bb = 2
+    message.repeated_nested_message.add().bb = 6
+    message.repeated_nested_message.add().bb = 5
+    message.repeated_nested_message.add().bb = 4
+    message.repeated_nested_message.sort(key=get_bb)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [1, 2, 3, 4, 5, 6])
+    message.repeated_nested_message.sort(key=get_bb, reverse=True)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [6, 5, 4, 3, 2, 1])
+    message.repeated_nested_message.sort(sort_function=cmp_bb)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [1, 2, 3, 4, 5, 6])
+    message.repeated_nested_message.sort(cmp=cmp_bb, reverse=True)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [6, 5, 4, 3, 2, 1])
+
+  def testRepeatedScalarFieldSortArguments(self):
+    """Check sorting a scalar field using list.sort() arguments."""
+    message = unittest_pb2.TestAllTypes()
+
+    abs_cmp = lambda a, b: cmp(abs(a), abs(b))
+    message.repeated_int32.append(-3)
+    message.repeated_int32.append(-2)
+    message.repeated_int32.append(-1)
+    message.repeated_int32.sort(key=abs)
+    self.assertEqual(list(message.repeated_int32), [-1, -2, -3])
+    message.repeated_int32.sort(key=abs, reverse=True)
+    self.assertEqual(list(message.repeated_int32), [-3, -2, -1])
+    message.repeated_int32.sort(sort_function=abs_cmp)
+    self.assertEqual(list(message.repeated_int32), [-1, -2, -3])
+    message.repeated_int32.sort(cmp=abs_cmp, reverse=True)
+    self.assertEqual(list(message.repeated_int32), [-3, -2, -1])
+
+    len_cmp = lambda a, b: cmp(len(a), len(b))
+    message.repeated_string.append('aaa')
+    message.repeated_string.append('bb')
+    message.repeated_string.append('c')
+    message.repeated_string.sort(key=len)
+    self.assertEqual(list(message.repeated_string), ['c', 'bb', 'aaa'])
+    message.repeated_string.sort(key=len, reverse=True)
+    self.assertEqual(list(message.repeated_string), ['aaa', 'bb', 'c'])
+    message.repeated_string.sort(sort_function=len_cmp)
+    self.assertEqual(list(message.repeated_string), ['c', 'bb', 'aaa'])
+    message.repeated_string.sort(cmp=len_cmp, reverse=True)
+    self.assertEqual(list(message.repeated_string), ['aaa', 'bb', 'c'])
+
+  def testParsingMerge(self):
+    """Check the merge behavior when a required or optional field appears
+    multiple times in the input."""
+    messages = [
+        unittest_pb2.TestAllTypes(),
+        unittest_pb2.TestAllTypes(),
+        unittest_pb2.TestAllTypes() ]
+    messages[0].optional_int32 = 1
+    messages[1].optional_int64 = 2
+    messages[2].optional_int32 = 3
+    messages[2].optional_string = 'hello'
+
+    merged_message = unittest_pb2.TestAllTypes()
+    merged_message.optional_int32 = 3
+    merged_message.optional_int64 = 2
+    merged_message.optional_string = 'hello'
+
+    generator = unittest_pb2.TestParsingMerge.RepeatedFieldsGenerator()
+    generator.field1.extend(messages)
+    generator.field2.extend(messages)
+    generator.field3.extend(messages)
+    generator.ext1.extend(messages)
+    generator.ext2.extend(messages)
+    generator.group1.add().field1.MergeFrom(messages[0])
+    generator.group1.add().field1.MergeFrom(messages[1])
+    generator.group1.add().field1.MergeFrom(messages[2])
+    generator.group2.add().field1.MergeFrom(messages[0])
+    generator.group2.add().field1.MergeFrom(messages[1])
+    generator.group2.add().field1.MergeFrom(messages[2])
+
+    data = generator.SerializeToString()
+    parsing_merge = unittest_pb2.TestParsingMerge()
+    parsing_merge.ParseFromString(data)
+
+    # Required and optional fields should be merged.
+    self.assertEqual(parsing_merge.required_all_types, merged_message)
+    self.assertEqual(parsing_merge.optional_all_types, merged_message)
+    self.assertEqual(parsing_merge.optionalgroup.optional_group_all_types,
+                     merged_message)
+    self.assertEqual(parsing_merge.Extensions[
+                     unittest_pb2.TestParsingMerge.optional_ext],
+                     merged_message)
+
+    # Repeated fields should not be merged.
+    self.assertEqual(len(parsing_merge.repeated_all_types), 3)
+    self.assertEqual(len(parsing_merge.repeatedgroup), 3)
+    self.assertEqual(len(parsing_merge.Extensions[
+        unittest_pb2.TestParsingMerge.repeated_ext]), 3)
+
+
+  def testSortEmptyRepeatedCompositeContainer(self):
+    """Exercise a scenario that has led to segfaults in the past.
+    """
+    m = unittest_pb2.TestAllTypes()
+    m.repeated_nested_message.sort()
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/service_reflection_test.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/service_reflection_test.py
new file mode 100755
index 0000000..e04f825
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/service_reflection_test.py
@@ -0,0 +1,136 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests for google.protobuf.internal.service_reflection."""
+
+__author__ = 'petar@google.com (Petar Petrov)'
+
+import unittest
+from google.protobuf import unittest_pb2
+from google.protobuf import service_reflection
+from google.protobuf import service
+
+
+class FooUnitTest(unittest.TestCase):
+
+  def testService(self):
+    class MockRpcChannel(service.RpcChannel):
+      def CallMethod(self, method, controller, request, response, callback):
+        self.method = method
+        self.controller = controller
+        self.request = request
+        callback(response)
+
+    class MockRpcController(service.RpcController):
+      def SetFailed(self, msg):
+        self.failure_message = msg
+
+    self.callback_response = None
+
+    class MyService(unittest_pb2.TestService):
+      pass
+
+    self.callback_response = None
+
+    def MyCallback(response):
+      self.callback_response = response
+
+    rpc_controller = MockRpcController()
+    channel = MockRpcChannel()
+    srvc = MyService()
+    srvc.Foo(rpc_controller, unittest_pb2.FooRequest(), MyCallback)
+    self.assertEqual('Method Foo not implemented.',
+                     rpc_controller.failure_message)
+    self.assertEqual(None, self.callback_response)
+
+    rpc_controller.failure_message = None
+
+    service_descriptor = unittest_pb2.TestService.GetDescriptor()
+    srvc.CallMethod(service_descriptor.methods[1], rpc_controller,
+                    unittest_pb2.BarRequest(), MyCallback)
+    self.assertEqual('Method Bar not implemented.',
+                     rpc_controller.failure_message)
+    self.assertEqual(None, self.callback_response)
+    
+    class MyServiceImpl(unittest_pb2.TestService):
+      def Foo(self, rpc_controller, request, done):
+        self.foo_called = True
+      def Bar(self, rpc_controller, request, done):
+        self.bar_called = True
+
+    srvc = MyServiceImpl()
+    rpc_controller.failure_message = None
+    srvc.Foo(rpc_controller, unittest_pb2.FooRequest(), MyCallback)
+    self.assertEqual(None, rpc_controller.failure_message)
+    self.assertEqual(True, srvc.foo_called)
+
+    rpc_controller.failure_message = None
+    srvc.CallMethod(service_descriptor.methods[1], rpc_controller,
+                    unittest_pb2.BarRequest(), MyCallback)
+    self.assertEqual(None, rpc_controller.failure_message)
+    self.assertEqual(True, srvc.bar_called)
+
+  def testServiceStub(self):
+    class MockRpcChannel(service.RpcChannel):
+      def CallMethod(self, method, controller, request,
+                     response_class, callback):
+        self.method = method
+        self.controller = controller
+        self.request = request
+        callback(response_class())
+
+    self.callback_response = None
+
+    def MyCallback(response):
+      self.callback_response = response
+
+    channel = MockRpcChannel()
+    stub = unittest_pb2.TestService_Stub(channel)
+    rpc_controller = 'controller'
+    request = 'request'
+
+    # GetDescriptor now static, still works as instance method for compatability
+    self.assertEqual(unittest_pb2.TestService_Stub.GetDescriptor(),
+                     stub.GetDescriptor())
+
+    # Invoke method.
+    stub.Foo(rpc_controller, request, MyCallback)
+
+    self.assertTrue(isinstance(self.callback_response,
+                               unittest_pb2.FooResponse))
+    self.assertEqual(request, channel.request)
+    self.assertEqual(rpc_controller, channel.controller)
+    self.assertEqual(stub.GetDescriptor().methods[0], channel.method)
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/test_util.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/test_util.py
new file mode 100755
index 0000000..e2c9db0
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/test_util.py
@@ -0,0 +1,651 @@
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Utilities for Python proto2 tests.
+
+This is intentionally modeled on C++ code in
+//google/protobuf/test_util.*.
+"""
+
+__author__ = 'robinson@google.com (Will Robinson)'
+
+import os.path
+
+from google.protobuf import unittest_import_pb2
+from google.protobuf import unittest_pb2
+
+
+def SetAllNonLazyFields(message):
+  """Sets every non-lazy field in the message to a unique value.
+
+  Args:
+    message: A unittest_pb2.TestAllTypes instance.
+  """
+
+  #
+  # Optional fields.
+  #
+
+  message.optional_int32    = 101
+  message.optional_int64    = 102
+  message.optional_uint32   = 103
+  message.optional_uint64   = 104
+  message.optional_sint32   = 105
+  message.optional_sint64   = 106
+  message.optional_fixed32  = 107
+  message.optional_fixed64  = 108
+  message.optional_sfixed32 = 109
+  message.optional_sfixed64 = 110
+  message.optional_float    = 111
+  message.optional_double   = 112
+  message.optional_bool     = True
+  # TODO(robinson): Firmly spec out and test how
+  # protos interact with unicode.  One specific example:
+  # what happens if we change the literal below to
+  # u'115'?  What *should* happen?  Still some discussion
+  # to finish with Kenton about bytes vs. strings
+  # and forcing everything to be utf8. :-/
+  message.optional_string   = '115'
+  message.optional_bytes    = '116'
+
+  message.optionalgroup.a = 117
+  message.optional_nested_message.bb = 118
+  message.optional_foreign_message.c = 119
+  message.optional_import_message.d = 120
+  message.optional_public_import_message.e = 126
+
+  message.optional_nested_enum = unittest_pb2.TestAllTypes.BAZ
+  message.optional_foreign_enum = unittest_pb2.FOREIGN_BAZ
+  message.optional_import_enum = unittest_import_pb2.IMPORT_BAZ
+
+  message.optional_string_piece = '124'
+  message.optional_cord = '125'
+
+  #
+  # Repeated fields.
+  #
+
+  message.repeated_int32.append(201)
+  message.repeated_int64.append(202)
+  message.repeated_uint32.append(203)
+  message.repeated_uint64.append(204)
+  message.repeated_sint32.append(205)
+  message.repeated_sint64.append(206)
+  message.repeated_fixed32.append(207)
+  message.repeated_fixed64.append(208)
+  message.repeated_sfixed32.append(209)
+  message.repeated_sfixed64.append(210)
+  message.repeated_float.append(211)
+  message.repeated_double.append(212)
+  message.repeated_bool.append(True)
+  message.repeated_string.append('215')
+  message.repeated_bytes.append('216')
+
+  message.repeatedgroup.add().a = 217
+  message.repeated_nested_message.add().bb = 218
+  message.repeated_foreign_message.add().c = 219
+  message.repeated_import_message.add().d = 220
+  message.repeated_lazy_message.add().bb = 227
+
+  message.repeated_nested_enum.append(unittest_pb2.TestAllTypes.BAR)
+  message.repeated_foreign_enum.append(unittest_pb2.FOREIGN_BAR)
+  message.repeated_import_enum.append(unittest_import_pb2.IMPORT_BAR)
+
+  message.repeated_string_piece.append('224')
+  message.repeated_cord.append('225')
+
+  # Add a second one of each field.
+  message.repeated_int32.append(301)
+  message.repeated_int64.append(302)
+  message.repeated_uint32.append(303)
+  message.repeated_uint64.append(304)
+  message.repeated_sint32.append(305)
+  message.repeated_sint64.append(306)
+  message.repeated_fixed32.append(307)
+  message.repeated_fixed64.append(308)
+  message.repeated_sfixed32.append(309)
+  message.repeated_sfixed64.append(310)
+  message.repeated_float.append(311)
+  message.repeated_double.append(312)
+  message.repeated_bool.append(False)
+  message.repeated_string.append('315')
+  message.repeated_bytes.append('316')
+
+  message.repeatedgroup.add().a = 317
+  message.repeated_nested_message.add().bb = 318
+  message.repeated_foreign_message.add().c = 319
+  message.repeated_import_message.add().d = 320
+  message.repeated_lazy_message.add().bb = 327
+
+  message.repeated_nested_enum.append(unittest_pb2.TestAllTypes.BAZ)
+  message.repeated_foreign_enum.append(unittest_pb2.FOREIGN_BAZ)
+  message.repeated_import_enum.append(unittest_import_pb2.IMPORT_BAZ)
+
+  message.repeated_string_piece.append('324')
+  message.repeated_cord.append('325')
+
+  #
+  # Fields that have defaults.
+  #
+
+  message.default_int32 = 401
+  message.default_int64 = 402
+  message.default_uint32 = 403
+  message.default_uint64 = 404
+  message.default_sint32 = 405
+  message.default_sint64 = 406
+  message.default_fixed32 = 407
+  message.default_fixed64 = 408
+  message.default_sfixed32 = 409
+  message.default_sfixed64 = 410
+  message.default_float = 411
+  message.default_double = 412
+  message.default_bool = False
+  message.default_string = '415'
+  message.default_bytes = '416'
+
+  message.default_nested_enum = unittest_pb2.TestAllTypes.FOO
+  message.default_foreign_enum = unittest_pb2.FOREIGN_FOO
+  message.default_import_enum = unittest_import_pb2.IMPORT_FOO
+
+  message.default_string_piece = '424'
+  message.default_cord = '425'
+
+
+def SetAllFields(message):
+  SetAllNonLazyFields(message)
+  message.optional_lazy_message.bb = 127
+
+
+def SetAllExtensions(message):
+  """Sets every extension in the message to a unique value.
+
+  Args:
+    message: A unittest_pb2.TestAllExtensions instance.
+  """
+
+  extensions = message.Extensions
+  pb2 = unittest_pb2
+  import_pb2 = unittest_import_pb2
+
+  #
+  # Optional fields.
+  #
+
+  extensions[pb2.optional_int32_extension] = 101
+  extensions[pb2.optional_int64_extension] = 102
+  extensions[pb2.optional_uint32_extension] = 103
+  extensions[pb2.optional_uint64_extension] = 104
+  extensions[pb2.optional_sint32_extension] = 105
+  extensions[pb2.optional_sint64_extension] = 106
+  extensions[pb2.optional_fixed32_extension] = 107
+  extensions[pb2.optional_fixed64_extension] = 108
+  extensions[pb2.optional_sfixed32_extension] = 109
+  extensions[pb2.optional_sfixed64_extension] = 110
+  extensions[pb2.optional_float_extension] = 111
+  extensions[pb2.optional_double_extension] = 112
+  extensions[pb2.optional_bool_extension] = True
+  extensions[pb2.optional_string_extension] = '115'
+  extensions[pb2.optional_bytes_extension] = '116'
+
+  extensions[pb2.optionalgroup_extension].a = 117
+  extensions[pb2.optional_nested_message_extension].bb = 118
+  extensions[pb2.optional_foreign_message_extension].c = 119
+  extensions[pb2.optional_import_message_extension].d = 120
+  extensions[pb2.optional_public_import_message_extension].e = 126
+  extensions[pb2.optional_lazy_message_extension].bb = 127
+
+  extensions[pb2.optional_nested_enum_extension] = pb2.TestAllTypes.BAZ
+  extensions[pb2.optional_nested_enum_extension] = pb2.TestAllTypes.BAZ
+  extensions[pb2.optional_foreign_enum_extension] = pb2.FOREIGN_BAZ
+  extensions[pb2.optional_import_enum_extension] = import_pb2.IMPORT_BAZ
+
+  extensions[pb2.optional_string_piece_extension] = '124'
+  extensions[pb2.optional_cord_extension] = '125'
+
+  #
+  # Repeated fields.
+  #
+
+  extensions[pb2.repeated_int32_extension].append(201)
+  extensions[pb2.repeated_int64_extension].append(202)
+  extensions[pb2.repeated_uint32_extension].append(203)
+  extensions[pb2.repeated_uint64_extension].append(204)
+  extensions[pb2.repeated_sint32_extension].append(205)
+  extensions[pb2.repeated_sint64_extension].append(206)
+  extensions[pb2.repeated_fixed32_extension].append(207)
+  extensions[pb2.repeated_fixed64_extension].append(208)
+  extensions[pb2.repeated_sfixed32_extension].append(209)
+  extensions[pb2.repeated_sfixed64_extension].append(210)
+  extensions[pb2.repeated_float_extension].append(211)
+  extensions[pb2.repeated_double_extension].append(212)
+  extensions[pb2.repeated_bool_extension].append(True)
+  extensions[pb2.repeated_string_extension].append('215')
+  extensions[pb2.repeated_bytes_extension].append('216')
+
+  extensions[pb2.repeatedgroup_extension].add().a = 217
+  extensions[pb2.repeated_nested_message_extension].add().bb = 218
+  extensions[pb2.repeated_foreign_message_extension].add().c = 219
+  extensions[pb2.repeated_import_message_extension].add().d = 220
+  extensions[pb2.repeated_lazy_message_extension].add().bb = 227
+
+  extensions[pb2.repeated_nested_enum_extension].append(pb2.TestAllTypes.BAR)
+  extensions[pb2.repeated_foreign_enum_extension].append(pb2.FOREIGN_BAR)
+  extensions[pb2.repeated_import_enum_extension].append(import_pb2.IMPORT_BAR)
+
+  extensions[pb2.repeated_string_piece_extension].append('224')
+  extensions[pb2.repeated_cord_extension].append('225')
+
+  # Append a second one of each field.
+  extensions[pb2.repeated_int32_extension].append(301)
+  extensions[pb2.repeated_int64_extension].append(302)
+  extensions[pb2.repeated_uint32_extension].append(303)
+  extensions[pb2.repeated_uint64_extension].append(304)
+  extensions[pb2.repeated_sint32_extension].append(305)
+  extensions[pb2.repeated_sint64_extension].append(306)
+  extensions[pb2.repeated_fixed32_extension].append(307)
+  extensions[pb2.repeated_fixed64_extension].append(308)
+  extensions[pb2.repeated_sfixed32_extension].append(309)
+  extensions[pb2.repeated_sfixed64_extension].append(310)
+  extensions[pb2.repeated_float_extension].append(311)
+  extensions[pb2.repeated_double_extension].append(312)
+  extensions[pb2.repeated_bool_extension].append(False)
+  extensions[pb2.repeated_string_extension].append('315')
+  extensions[pb2.repeated_bytes_extension].append('316')
+
+  extensions[pb2.repeatedgroup_extension].add().a = 317
+  extensions[pb2.repeated_nested_message_extension].add().bb = 318
+  extensions[pb2.repeated_foreign_message_extension].add().c = 319
+  extensions[pb2.repeated_import_message_extension].add().d = 320
+  extensions[pb2.repeated_lazy_message_extension].add().bb = 327
+
+  extensions[pb2.repeated_nested_enum_extension].append(pb2.TestAllTypes.BAZ)
+  extensions[pb2.repeated_foreign_enum_extension].append(pb2.FOREIGN_BAZ)
+  extensions[pb2.repeated_import_enum_extension].append(import_pb2.IMPORT_BAZ)
+
+  extensions[pb2.repeated_string_piece_extension].append('324')
+  extensions[pb2.repeated_cord_extension].append('325')
+
+  #
+  # Fields with defaults.
+  #
+
+  extensions[pb2.default_int32_extension] = 401
+  extensions[pb2.default_int64_extension] = 402
+  extensions[pb2.default_uint32_extension] = 403
+  extensions[pb2.default_uint64_extension] = 404
+  extensions[pb2.default_sint32_extension] = 405
+  extensions[pb2.default_sint64_extension] = 406
+  extensions[pb2.default_fixed32_extension] = 407
+  extensions[pb2.default_fixed64_extension] = 408
+  extensions[pb2.default_sfixed32_extension] = 409
+  extensions[pb2.default_sfixed64_extension] = 410
+  extensions[pb2.default_float_extension] = 411
+  extensions[pb2.default_double_extension] = 412
+  extensions[pb2.default_bool_extension] = False
+  extensions[pb2.default_string_extension] = '415'
+  extensions[pb2.default_bytes_extension] = '416'
+
+  extensions[pb2.default_nested_enum_extension] = pb2.TestAllTypes.FOO
+  extensions[pb2.default_foreign_enum_extension] = pb2.FOREIGN_FOO
+  extensions[pb2.default_import_enum_extension] = import_pb2.IMPORT_FOO
+
+  extensions[pb2.default_string_piece_extension] = '424'
+  extensions[pb2.default_cord_extension] = '425'
+
+
+def SetAllFieldsAndExtensions(message):
+  """Sets every field and extension in the message to a unique value.
+
+  Args:
+    message: A unittest_pb2.TestAllExtensions message.
+  """
+  message.my_int = 1
+  message.my_string = 'foo'
+  message.my_float = 1.0
+  message.Extensions[unittest_pb2.my_extension_int] = 23
+  message.Extensions[unittest_pb2.my_extension_string] = 'bar'
+
+
+def ExpectAllFieldsAndExtensionsInOrder(serialized):
+  """Ensures that serialized is the serialization we expect for a message
+  filled with SetAllFieldsAndExtensions().  (Specifically, ensures that the
+  serialization is in canonical, tag-number order).
+  """
+  my_extension_int = unittest_pb2.my_extension_int
+  my_extension_string = unittest_pb2.my_extension_string
+  expected_strings = []
+  message = unittest_pb2.TestFieldOrderings()
+  message.my_int = 1  # Field 1.
+  expected_strings.append(message.SerializeToString())
+  message.Clear()
+  message.Extensions[my_extension_int] = 23  # Field 5.
+  expected_strings.append(message.SerializeToString())
+  message.Clear()
+  message.my_string = 'foo'  # Field 11.
+  expected_strings.append(message.SerializeToString())
+  message.Clear()
+  message.Extensions[my_extension_string] = 'bar'  # Field 50.
+  expected_strings.append(message.SerializeToString())
+  message.Clear()
+  message.my_float = 1.0
+  expected_strings.append(message.SerializeToString())
+  message.Clear()
+  expected = ''.join(expected_strings)
+
+  if expected != serialized:
+    raise ValueError('Expected %r, found %r' % (expected, serialized))
+
+
+def ExpectAllFieldsSet(test_case, message):
+  """Check all fields for correct values have after Set*Fields() is called."""
+  test_case.assertTrue(message.HasField('optional_int32'))
+  test_case.assertTrue(message.HasField('optional_int64'))
+  test_case.assertTrue(message.HasField('optional_uint32'))
+  test_case.assertTrue(message.HasField('optional_uint64'))
+  test_case.assertTrue(message.HasField('optional_sint32'))
+  test_case.assertTrue(message.HasField('optional_sint64'))
+  test_case.assertTrue(message.HasField('optional_fixed32'))
+  test_case.assertTrue(message.HasField('optional_fixed64'))
+  test_case.assertTrue(message.HasField('optional_sfixed32'))
+  test_case.assertTrue(message.HasField('optional_sfixed64'))
+  test_case.assertTrue(message.HasField('optional_float'))
+  test_case.assertTrue(message.HasField('optional_double'))
+  test_case.assertTrue(message.HasField('optional_bool'))
+  test_case.assertTrue(message.HasField('optional_string'))
+  test_case.assertTrue(message.HasField('optional_bytes'))
+
+  test_case.assertTrue(message.HasField('optionalgroup'))
+  test_case.assertTrue(message.HasField('optional_nested_message'))
+  test_case.assertTrue(message.HasField('optional_foreign_message'))
+  test_case.assertTrue(message.HasField('optional_import_message'))
+
+  test_case.assertTrue(message.optionalgroup.HasField('a'))
+  test_case.assertTrue(message.optional_nested_message.HasField('bb'))
+  test_case.assertTrue(message.optional_foreign_message.HasField('c'))
+  test_case.assertTrue(message.optional_import_message.HasField('d'))
+
+  test_case.assertTrue(message.HasField('optional_nested_enum'))
+  test_case.assertTrue(message.HasField('optional_foreign_enum'))
+  test_case.assertTrue(message.HasField('optional_import_enum'))
+
+  test_case.assertTrue(message.HasField('optional_string_piece'))
+  test_case.assertTrue(message.HasField('optional_cord'))
+
+  test_case.assertEqual(101, message.optional_int32)
+  test_case.assertEqual(102, message.optional_int64)
+  test_case.assertEqual(103, message.optional_uint32)
+  test_case.assertEqual(104, message.optional_uint64)
+  test_case.assertEqual(105, message.optional_sint32)
+  test_case.assertEqual(106, message.optional_sint64)
+  test_case.assertEqual(107, message.optional_fixed32)
+  test_case.assertEqual(108, message.optional_fixed64)
+  test_case.assertEqual(109, message.optional_sfixed32)
+  test_case.assertEqual(110, message.optional_sfixed64)
+  test_case.assertEqual(111, message.optional_float)
+  test_case.assertEqual(112, message.optional_double)
+  test_case.assertEqual(True, message.optional_bool)
+  test_case.assertEqual('115', message.optional_string)
+  test_case.assertEqual('116', message.optional_bytes)
+
+  test_case.assertEqual(117, message.optionalgroup.a)
+  test_case.assertEqual(118, message.optional_nested_message.bb)
+  test_case.assertEqual(119, message.optional_foreign_message.c)
+  test_case.assertEqual(120, message.optional_import_message.d)
+  test_case.assertEqual(126, message.optional_public_import_message.e)
+  test_case.assertEqual(127, message.optional_lazy_message.bb)
+
+  test_case.assertEqual(unittest_pb2.TestAllTypes.BAZ,
+                        message.optional_nested_enum)
+  test_case.assertEqual(unittest_pb2.FOREIGN_BAZ,
+                        message.optional_foreign_enum)
+  test_case.assertEqual(unittest_import_pb2.IMPORT_BAZ,
+                        message.optional_import_enum)
+
+  # -----------------------------------------------------------------
+
+  test_case.assertEqual(2, len(message.repeated_int32))
+  test_case.assertEqual(2, len(message.repeated_int64))
+  test_case.assertEqual(2, len(message.repeated_uint32))
+  test_case.assertEqual(2, len(message.repeated_uint64))
+  test_case.assertEqual(2, len(message.repeated_sint32))
+  test_case.assertEqual(2, len(message.repeated_sint64))
+  test_case.assertEqual(2, len(message.repeated_fixed32))
+  test_case.assertEqual(2, len(message.repeated_fixed64))
+  test_case.assertEqual(2, len(message.repeated_sfixed32))
+  test_case.assertEqual(2, len(message.repeated_sfixed64))
+  test_case.assertEqual(2, len(message.repeated_float))
+  test_case.assertEqual(2, len(message.repeated_double))
+  test_case.assertEqual(2, len(message.repeated_bool))
+  test_case.assertEqual(2, len(message.repeated_string))
+  test_case.assertEqual(2, len(message.repeated_bytes))
+
+  test_case.assertEqual(2, len(message.repeatedgroup))
+  test_case.assertEqual(2, len(message.repeated_nested_message))
+  test_case.assertEqual(2, len(message.repeated_foreign_message))
+  test_case.assertEqual(2, len(message.repeated_import_message))
+  test_case.assertEqual(2, len(message.repeated_nested_enum))
+  test_case.assertEqual(2, len(message.repeated_foreign_enum))
+  test_case.assertEqual(2, len(message.repeated_import_enum))
+
+  test_case.assertEqual(2, len(message.repeated_string_piece))
+  test_case.assertEqual(2, len(message.repeated_cord))
+
+  test_case.assertEqual(201, message.repeated_int32[0])
+  test_case.assertEqual(202, message.repeated_int64[0])
+  test_case.assertEqual(203, message.repeated_uint32[0])
+  test_case.assertEqual(204, message.repeated_uint64[0])
+  test_case.assertEqual(205, message.repeated_sint32[0])
+  test_case.assertEqual(206, message.repeated_sint64[0])
+  test_case.assertEqual(207, message.repeated_fixed32[0])
+  test_case.assertEqual(208, message.repeated_fixed64[0])
+  test_case.assertEqual(209, message.repeated_sfixed32[0])
+  test_case.assertEqual(210, message.repeated_sfixed64[0])
+  test_case.assertEqual(211, message.repeated_float[0])
+  test_case.assertEqual(212, message.repeated_double[0])
+  test_case.assertEqual(True, message.repeated_bool[0])
+  test_case.assertEqual('215', message.repeated_string[0])
+  test_case.assertEqual('216', message.repeated_bytes[0])
+
+  test_case.assertEqual(217, message.repeatedgroup[0].a)
+  test_case.assertEqual(218, message.repeated_nested_message[0].bb)
+  test_case.assertEqual(219, message.repeated_foreign_message[0].c)
+  test_case.assertEqual(220, message.repeated_import_message[0].d)
+  test_case.assertEqual(227, message.repeated_lazy_message[0].bb)
+
+  test_case.assertEqual(unittest_pb2.TestAllTypes.BAR,
+                        message.repeated_nested_enum[0])
+  test_case.assertEqual(unittest_pb2.FOREIGN_BAR,
+                        message.repeated_foreign_enum[0])
+  test_case.assertEqual(unittest_import_pb2.IMPORT_BAR,
+                        message.repeated_import_enum[0])
+
+  test_case.assertEqual(301, message.repeated_int32[1])
+  test_case.assertEqual(302, message.repeated_int64[1])
+  test_case.assertEqual(303, message.repeated_uint32[1])
+  test_case.assertEqual(304, message.repeated_uint64[1])
+  test_case.assertEqual(305, message.repeated_sint32[1])
+  test_case.assertEqual(306, message.repeated_sint64[1])
+  test_case.assertEqual(307, message.repeated_fixed32[1])
+  test_case.assertEqual(308, message.repeated_fixed64[1])
+  test_case.assertEqual(309, message.repeated_sfixed32[1])
+  test_case.assertEqual(310, message.repeated_sfixed64[1])
+  test_case.assertEqual(311, message.repeated_float[1])
+  test_case.assertEqual(312, message.repeated_double[1])
+  test_case.assertEqual(False, message.repeated_bool[1])
+  test_case.assertEqual('315', message.repeated_string[1])
+  test_case.assertEqual('316', message.repeated_bytes[1])
+
+  test_case.assertEqual(317, message.repeatedgroup[1].a)
+  test_case.assertEqual(318, message.repeated_nested_message[1].bb)
+  test_case.assertEqual(319, message.repeated_foreign_message[1].c)
+  test_case.assertEqual(320, message.repeated_import_message[1].d)
+  test_case.assertEqual(327, message.repeated_lazy_message[1].bb)
+
+  test_case.assertEqual(unittest_pb2.TestAllTypes.BAZ,
+                        message.repeated_nested_enum[1])
+  test_case.assertEqual(unittest_pb2.FOREIGN_BAZ,
+                        message.repeated_foreign_enum[1])
+  test_case.assertEqual(unittest_import_pb2.IMPORT_BAZ,
+                        message.repeated_import_enum[1])
+
+  # -----------------------------------------------------------------
+
+  test_case.assertTrue(message.HasField('default_int32'))
+  test_case.assertTrue(message.HasField('default_int64'))
+  test_case.assertTrue(message.HasField('default_uint32'))
+  test_case.assertTrue(message.HasField('default_uint64'))
+  test_case.assertTrue(message.HasField('default_sint32'))
+  test_case.assertTrue(message.HasField('default_sint64'))
+  test_case.assertTrue(message.HasField('default_fixed32'))
+  test_case.assertTrue(message.HasField('default_fixed64'))
+  test_case.assertTrue(message.HasField('default_sfixed32'))
+  test_case.assertTrue(message.HasField('default_sfixed64'))
+  test_case.assertTrue(message.HasField('default_float'))
+  test_case.assertTrue(message.HasField('default_double'))
+  test_case.assertTrue(message.HasField('default_bool'))
+  test_case.assertTrue(message.HasField('default_string'))
+  test_case.assertTrue(message.HasField('default_bytes'))
+
+  test_case.assertTrue(message.HasField('default_nested_enum'))
+  test_case.assertTrue(message.HasField('default_foreign_enum'))
+  test_case.assertTrue(message.HasField('default_import_enum'))
+
+  test_case.assertEqual(401, message.default_int32)
+  test_case.assertEqual(402, message.default_int64)
+  test_case.assertEqual(403, message.default_uint32)
+  test_case.assertEqual(404, message.default_uint64)
+  test_case.assertEqual(405, message.default_sint32)
+  test_case.assertEqual(406, message.default_sint64)
+  test_case.assertEqual(407, message.default_fixed32)
+  test_case.assertEqual(408, message.default_fixed64)
+  test_case.assertEqual(409, message.default_sfixed32)
+  test_case.assertEqual(410, message.default_sfixed64)
+  test_case.assertEqual(411, message.default_float)
+  test_case.assertEqual(412, message.default_double)
+  test_case.assertEqual(False, message.default_bool)
+  test_case.assertEqual('415', message.default_string)
+  test_case.assertEqual('416', message.default_bytes)
+
+  test_case.assertEqual(unittest_pb2.TestAllTypes.FOO,
+                        message.default_nested_enum)
+  test_case.assertEqual(unittest_pb2.FOREIGN_FOO,
+                        message.default_foreign_enum)
+  test_case.assertEqual(unittest_import_pb2.IMPORT_FOO,
+                        message.default_import_enum)
+
+def GoldenFile(filename):
+  """Finds the given golden file and returns a file object representing it."""
+
+  # Search up the directory tree looking for the C++ protobuf source code.
+  path = '.'
+  while os.path.exists(path):
+    if os.path.exists(os.path.join(path, 'tests/google/protobuf/internal')):
+      # Found it.  Load the golden file from the testdata directory.
+      full_path = os.path.join(path, 'tests/google/protobuf/internal', filename)
+      return open(full_path, 'rb')
+    path = os.path.join(path, '..')
+
+  raise RuntimeError(
+    'Could not find golden files.  This test must be run from within the '
+    'protobuf source package so that it can read test data files from the '
+    'C++ source tree.')
+
+
+def SetAllPackedFields(message):
+  """Sets every field in the message to a unique value.
+
+  Args:
+    message: A unittest_pb2.TestPackedTypes instance.
+  """
+  message.packed_int32.extend([601, 701])
+  message.packed_int64.extend([602, 702])
+  message.packed_uint32.extend([603, 703])
+  message.packed_uint64.extend([604, 704])
+  message.packed_sint32.extend([605, 705])
+  message.packed_sint64.extend([606, 706])
+  message.packed_fixed32.extend([607, 707])
+  message.packed_fixed64.extend([608, 708])
+  message.packed_sfixed32.extend([609, 709])
+  message.packed_sfixed64.extend([610, 710])
+  message.packed_float.extend([611.0, 711.0])
+  message.packed_double.extend([612.0, 712.0])
+  message.packed_bool.extend([True, False])
+  message.packed_enum.extend([unittest_pb2.FOREIGN_BAR,
+                              unittest_pb2.FOREIGN_BAZ])
+
+
+def SetAllPackedExtensions(message):
+  """Sets every extension in the message to a unique value.
+
+  Args:
+    message: A unittest_pb2.TestPackedExtensions instance.
+  """
+  extensions = message.Extensions
+  pb2 = unittest_pb2
+
+  extensions[pb2.packed_int32_extension].extend([601, 701])
+  extensions[pb2.packed_int64_extension].extend([602, 702])
+  extensions[pb2.packed_uint32_extension].extend([603, 703])
+  extensions[pb2.packed_uint64_extension].extend([604, 704])
+  extensions[pb2.packed_sint32_extension].extend([605, 705])
+  extensions[pb2.packed_sint64_extension].extend([606, 706])
+  extensions[pb2.packed_fixed32_extension].extend([607, 707])
+  extensions[pb2.packed_fixed64_extension].extend([608, 708])
+  extensions[pb2.packed_sfixed32_extension].extend([609, 709])
+  extensions[pb2.packed_sfixed64_extension].extend([610, 710])
+  extensions[pb2.packed_float_extension].extend([611.0, 711.0])
+  extensions[pb2.packed_double_extension].extend([612.0, 712.0])
+  extensions[pb2.packed_bool_extension].extend([True, False])
+  extensions[pb2.packed_enum_extension].extend([unittest_pb2.FOREIGN_BAR,
+                                                unittest_pb2.FOREIGN_BAZ])
+
+
+def SetAllUnpackedFields(message):
+  """Sets every field in the message to a unique value.
+
+  Args:
+    message: A unittest_pb2.TestUnpackedTypes instance.
+  """
+  message.unpacked_int32.extend([601, 701])
+  message.unpacked_int64.extend([602, 702])
+  message.unpacked_uint32.extend([603, 703])
+  message.unpacked_uint64.extend([604, 704])
+  message.unpacked_sint32.extend([605, 705])
+  message.unpacked_sint64.extend([606, 706])
+  message.unpacked_fixed32.extend([607, 707])
+  message.unpacked_fixed64.extend([608, 708])
+  message.unpacked_sfixed32.extend([609, 709])
+  message.unpacked_sfixed64.extend([610, 710])
+  message.unpacked_float.extend([611.0, 711.0])
+  message.unpacked_double.extend([612.0, 712.0])
+  message.unpacked_bool.extend([True, False])
+  message.unpacked_enum.extend([unittest_pb2.FOREIGN_BAR,
+                                unittest_pb2.FOREIGN_BAZ])
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_test.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_test.py
new file mode 100755
index 0000000..8267cd2
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_test.py
@@ -0,0 +1,619 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test for google.protobuf.text_format."""
+
+__author__ = 'kenton@google.com (Kenton Varda)'
+
+import difflib
+import re
+
+import unittest
+from google.protobuf import text_format
+from google.protobuf.internal import test_util
+from google.protobuf import unittest_pb2
+from google.protobuf import unittest_mset_pb2
+
+
+class TextFormatTest(unittest.TestCase):
+  def ReadGolden(self, golden_filename):
+    f = test_util.GoldenFile(golden_filename)
+    golden_lines = f.readlines()
+    f.close()
+    return golden_lines
+
+  def CompareToGoldenFile(self, text, golden_filename):
+    golden_lines = self.ReadGolden(golden_filename)
+    self.CompareToGoldenLines(text, golden_lines)
+
+  def CompareToGoldenText(self, text, golden_text):
+    self.CompareToGoldenLines(text, golden_text.splitlines(1))
+
+  def CompareToGoldenLines(self, text, golden_lines):
+    actual_lines = text.splitlines(1)
+    self.assertEqual(golden_lines, actual_lines,
+      "Text doesn't match golden.  Diff:\n" +
+      ''.join(difflib.ndiff(golden_lines, actual_lines)))
+
+  def testPrintAllFields(self):
+    message = unittest_pb2.TestAllTypes()
+    test_util.SetAllFields(message)
+    self.CompareToGoldenFile(
+      self.RemoveRedundantZeros(text_format.MessageToString(message)),
+      'text_format_unittest_data.txt')
+
+  def testPrintAllExtensions(self):
+    message = unittest_pb2.TestAllExtensions()
+    test_util.SetAllExtensions(message)
+    self.CompareToGoldenFile(
+      self.RemoveRedundantZeros(text_format.MessageToString(message)),
+      'text_format_unittest_extensions_data.txt')
+
+  def testPrintMessageSet(self):
+    message = unittest_mset_pb2.TestMessageSetContainer()
+    ext1 = unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
+    ext2 = unittest_mset_pb2.TestMessageSetExtension2.message_set_extension
+    message.message_set.Extensions[ext1].i = 23
+    message.message_set.Extensions[ext2].str = 'foo'
+    self.CompareToGoldenText(text_format.MessageToString(message),
+      'message_set {\n'
+      '  [protobuf_unittest.TestMessageSetExtension1] {\n'
+      '    i: 23\n'
+      '  }\n'
+      '  [protobuf_unittest.TestMessageSetExtension2] {\n'
+      '    str: \"foo\"\n'
+      '  }\n'
+      '}\n')
+
+  """
+  def testPrintBadEnumValue(self):
+    message = unittest_pb2.TestAllTypes()
+    message.optional_nested_enum = 100
+    message.optional_foreign_enum = 101
+    message.optional_import_enum = 102
+    self.CompareToGoldenText(
+        text_format.MessageToString(message),
+        'optional_nested_enum: 100\n'
+        'optional_foreign_enum: 101\n'
+        'optional_import_enum: 102\n')
+
+  def testPrintBadEnumValueExtensions(self):
+    message = unittest_pb2.TestAllExtensions()
+    message.Extensions[unittest_pb2.optional_nested_enum_extension] = 100
+    message.Extensions[unittest_pb2.optional_foreign_enum_extension] = 101
+    message.Extensions[unittest_pb2.optional_import_enum_extension] = 102
+    self.CompareToGoldenText(
+        text_format.MessageToString(message),
+        '[protobuf_unittest.optional_nested_enum_extension]: 100\n'
+        '[protobuf_unittest.optional_foreign_enum_extension]: 101\n'
+        '[protobuf_unittest.optional_import_enum_extension]: 102\n')
+  """
+
+  def testPrintExotic(self):
+    message = unittest_pb2.TestAllTypes()
+    message.repeated_int64.append(-9223372036854775808)
+    message.repeated_uint64.append(18446744073709551615)
+    message.repeated_double.append(123.456)
+    message.repeated_double.append(1.23e22)
+    message.repeated_double.append(1.23e-18)
+    message.repeated_string.append('\000\001\a\b\f\n\r\t\v\\\'"')
+    message.repeated_string.append(u'\u00fc\ua71f')
+    self.CompareToGoldenText(
+      self.RemoveRedundantZeros(text_format.MessageToString(message)),
+      'repeated_int64: -9223372036854775808\n'
+      'repeated_uint64: 18446744073709551615\n'
+      'repeated_double: 123.456\n'
+      'repeated_double: 1.23e+22\n'
+      'repeated_double: 1.23e-18\n'
+      'repeated_string: '
+        '"\\000\\001\\007\\010\\014\\n\\r\\t\\013\\\\\\\'\\""\n'
+      'repeated_string: "\\303\\274\\352\\234\\237"\n')
+
+  def testPrintNestedMessageAsOneLine(self):
+    message = unittest_pb2.TestAllTypes()
+    msg = message.repeated_nested_message.add()
+    msg.bb = 42;
+    self.CompareToGoldenText(
+        text_format.MessageToString(message, as_one_line=True),
+        'repeated_nested_message { bb: 42 }')
+
+  def testPrintRepeatedFieldsAsOneLine(self):
+    message = unittest_pb2.TestAllTypes()
+    message.repeated_int32.append(1)
+    message.repeated_int32.append(1)
+    message.repeated_int32.append(3)
+    message.repeated_string.append("Google")
+    message.repeated_string.append("Zurich")
+    self.CompareToGoldenText(
+        text_format.MessageToString(message, as_one_line=True),
+        'repeated_int32: 1 repeated_int32: 1 repeated_int32: 3 '
+        'repeated_string: "Google" repeated_string: "Zurich"')
+
+  def testPrintNestedNewLineInStringAsOneLine(self):
+    message = unittest_pb2.TestAllTypes()
+    message.optional_string = "a\nnew\nline"
+    self.CompareToGoldenText(
+        text_format.MessageToString(message, as_one_line=True),
+        'optional_string: "a\\nnew\\nline"')
+
+  def testPrintMessageSetAsOneLine(self):
+    message = unittest_mset_pb2.TestMessageSetContainer()
+    ext1 = unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
+    ext2 = unittest_mset_pb2.TestMessageSetExtension2.message_set_extension
+    message.message_set.Extensions[ext1].i = 23
+    message.message_set.Extensions[ext2].str = 'foo'
+    self.CompareToGoldenText(
+        text_format.MessageToString(message, as_one_line=True),
+        'message_set {'
+        ' [protobuf_unittest.TestMessageSetExtension1] {'
+        ' i: 23'
+        ' }'
+        ' [protobuf_unittest.TestMessageSetExtension2] {'
+        ' str: \"foo\"'
+        ' }'
+        ' }')
+
+  def testPrintExoticAsOneLine(self):
+    message = unittest_pb2.TestAllTypes()
+    message.repeated_int64.append(-9223372036854775808)
+    message.repeated_uint64.append(18446744073709551615)
+    message.repeated_double.append(123.456)
+    message.repeated_double.append(1.23e22)
+    message.repeated_double.append(1.23e-18)
+    message.repeated_string.append('\000\001\a\b\f\n\r\t\v\\\'"')
+    message.repeated_string.append(u'\u00fc\ua71f')
+    self.CompareToGoldenText(
+      self.RemoveRedundantZeros(
+          text_format.MessageToString(message, as_one_line=True)),
+      'repeated_int64: -9223372036854775808'
+      ' repeated_uint64: 18446744073709551615'
+      ' repeated_double: 123.456'
+      ' repeated_double: 1.23e+22'
+      ' repeated_double: 1.23e-18'
+      ' repeated_string: '
+      '"\\000\\001\\007\\010\\014\\n\\r\\t\\013\\\\\\\'\\""'
+      ' repeated_string: "\\303\\274\\352\\234\\237"')
+
+  def testRoundTripExoticAsOneLine(self):
+    message = unittest_pb2.TestAllTypes()
+    message.repeated_int64.append(-9223372036854775808)
+    message.repeated_uint64.append(18446744073709551615)
+    message.repeated_double.append(123.456)
+    message.repeated_double.append(1.23e22)
+    message.repeated_double.append(1.23e-18)
+    message.repeated_string.append('\000\001\a\b\f\n\r\t\v\\\'"')
+    message.repeated_string.append(u'\u00fc\ua71f')
+
+    # Test as_utf8 = False.
+    wire_text = text_format.MessageToString(
+        message, as_one_line=True, as_utf8=False)
+    parsed_message = unittest_pb2.TestAllTypes()
+    text_format.Merge(wire_text, parsed_message)
+    self.assertEquals(message, parsed_message)
+
+    # Test as_utf8 = True.
+    wire_text = text_format.MessageToString(
+        message, as_one_line=True, as_utf8=True)
+    parsed_message = unittest_pb2.TestAllTypes()
+    text_format.Merge(wire_text, parsed_message)
+    self.assertEquals(message, parsed_message)
+
+  def testPrintRawUtf8String(self):
+    message = unittest_pb2.TestAllTypes()
+    message.repeated_string.append(u'\u00fc\ua71f')
+    text = text_format.MessageToString(message, as_utf8 = True)
+    self.CompareToGoldenText(text, 'repeated_string: "\303\274\352\234\237"\n')
+    parsed_message = unittest_pb2.TestAllTypes()
+    text_format.Merge(text, parsed_message)
+    self.assertEquals(message, parsed_message)
+
+  def testMessageToString(self):
+    message = unittest_pb2.ForeignMessage()
+    message.c = 123
+    self.assertEqual('c: 123\n', str(message))
+
+  def RemoveRedundantZeros(self, text):
+    # Some platforms print 1e+5 as 1e+005.  This is fine, but we need to remove
+    # these zeros in order to match the golden file.
+    text = text.replace('e+0','e+').replace('e+0','e+') \
+               .replace('e-0','e-').replace('e-0','e-')
+    # Floating point fields are printed with .0 suffix even if they are
+    # actualy integer numbers.
+    text = re.compile('\.0$', re.MULTILINE).sub('', text)
+    return text
+
+  def testMergeGolden(self):
+    golden_text = '\n'.join(self.ReadGolden('text_format_unittest_data.txt'))
+    parsed_message = unittest_pb2.TestAllTypes()
+    text_format.Merge(golden_text, parsed_message)
+
+    message = unittest_pb2.TestAllTypes()
+    test_util.SetAllFields(message)
+    self.assertEquals(message, parsed_message)
+
+  def testMergeGoldenExtensions(self):
+    golden_text = '\n'.join(self.ReadGolden(
+        'text_format_unittest_extensions_data.txt'))
+    parsed_message = unittest_pb2.TestAllExtensions()
+    text_format.Merge(golden_text, parsed_message)
+
+    message = unittest_pb2.TestAllExtensions()
+    test_util.SetAllExtensions(message)
+    self.assertEquals(message, parsed_message)
+
+  def testMergeAllFields(self):
+    message = unittest_pb2.TestAllTypes()
+    test_util.SetAllFields(message)
+    ascii_text = text_format.MessageToString(message)
+
+    parsed_message = unittest_pb2.TestAllTypes()
+    text_format.Merge(ascii_text, parsed_message)
+    self.assertEqual(message, parsed_message)
+    test_util.ExpectAllFieldsSet(self, message)
+
+  def testMergeAllExtensions(self):
+    message = unittest_pb2.TestAllExtensions()
+    test_util.SetAllExtensions(message)
+    ascii_text = text_format.MessageToString(message)
+
+    parsed_message = unittest_pb2.TestAllExtensions()
+    text_format.Merge(ascii_text, parsed_message)
+    self.assertEqual(message, parsed_message)
+
+  def testMergeMessageSet(self):
+    message = unittest_pb2.TestAllTypes()
+    text = ('repeated_uint64: 1\n'
+            'repeated_uint64: 2\n')
+    text_format.Merge(text, message)
+    self.assertEqual(1, message.repeated_uint64[0])
+    self.assertEqual(2, message.repeated_uint64[1])
+
+    message = unittest_mset_pb2.TestMessageSetContainer()
+    text = ('message_set {\n'
+            '  [protobuf_unittest.TestMessageSetExtension1] {\n'
+            '    i: 23\n'
+            '  }\n'
+            '  [protobuf_unittest.TestMessageSetExtension2] {\n'
+            '    str: \"foo\"\n'
+            '  }\n'
+            '}\n')
+    text_format.Merge(text, message)
+    ext1 = unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
+    ext2 = unittest_mset_pb2.TestMessageSetExtension2.message_set_extension
+    self.assertEquals(23, message.message_set.Extensions[ext1].i)
+    self.assertEquals('foo', message.message_set.Extensions[ext2].str)
+
+  def testMergeExotic(self):
+    message = unittest_pb2.TestAllTypes()
+    text = ('repeated_int64: -9223372036854775808\n'
+            'repeated_uint64: 18446744073709551615\n'
+            'repeated_double: 123.456\n'
+            'repeated_double: 1.23e+22\n'
+            'repeated_double: 1.23e-18\n'
+            'repeated_string: \n'
+            '"\\000\\001\\007\\010\\014\\n\\r\\t\\013\\\\\\\'\\""\n'
+            'repeated_string: "foo" \'corge\' "grault"\n'
+            'repeated_string: "\\303\\274\\352\\234\\237"\n'
+            'repeated_string: "\\xc3\\xbc"\n'
+            'repeated_string: "\xc3\xbc"\n')
+    text_format.Merge(text, message)
+
+    self.assertEqual(-9223372036854775808, message.repeated_int64[0])
+    self.assertEqual(18446744073709551615, message.repeated_uint64[0])
+    self.assertEqual(123.456, message.repeated_double[0])
+    self.assertEqual(1.23e22, message.repeated_double[1])
+    self.assertEqual(1.23e-18, message.repeated_double[2])
+    self.assertEqual(
+        '\000\001\a\b\f\n\r\t\v\\\'"', message.repeated_string[0])
+    self.assertEqual('foocorgegrault', message.repeated_string[1])
+    self.assertEqual(u'\u00fc\ua71f', message.repeated_string[2])
+    self.assertEqual(u'\u00fc', message.repeated_string[3])
+
+  def testMergeEmptyText(self):
+    message = unittest_pb2.TestAllTypes()
+    text = ''
+    text_format.Merge(text, message)
+    self.assertEquals(unittest_pb2.TestAllTypes(), message)
+
+  def testMergeInvalidUtf8(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'repeated_string: "\\xc3\\xc3"'
+    self.assertRaises(text_format.ParseError, text_format.Merge, text, message)
+
+  def testMergeSingleWord(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'foo'
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:1 : Message type "protobuf_unittest.TestAllTypes" has no field named '
+         '"foo".'),
+        text_format.Merge, text, message)
+
+  def testMergeUnknownField(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'unknown_field: 8\n'
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:1 : Message type "protobuf_unittest.TestAllTypes" has no field named '
+         '"unknown_field".'),
+        text_format.Merge, text, message)
+
+  def testMergeBadExtension(self):
+    message = unittest_pb2.TestAllExtensions()
+    text = '[unknown_extension]: 8\n'
+    self.assertRaises(
+        text_format.ParseError,
+        text_format.Merge, text, message)
+    message = unittest_pb2.TestAllTypes()
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:2 : Message type "protobuf_unittest.TestAllTypes" does not have '
+         'extensions.'),
+        text_format.Merge, text, message)
+
+  def testMergeGroupNotClosed(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'RepeatedGroup: <'
+    self.assertRaisesWithMessage(
+        text_format.ParseError, '1:16 : Expected ">".',
+        text_format.Merge, text, message)
+
+    text = 'RepeatedGroup: {'
+    self.assertRaisesWithMessage(
+        text_format.ParseError, '1:16 : Expected "}".',
+        text_format.Merge, text, message)
+
+  def testMergeEmptyGroup(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'OptionalGroup: {}'
+    text_format.Merge(text, message)
+    self.assertTrue(message.HasField('optionalgroup'))
+
+    message.Clear()
+
+    message = unittest_pb2.TestAllTypes()
+    text = 'OptionalGroup: <>'
+    text_format.Merge(text, message)
+    self.assertTrue(message.HasField('optionalgroup'))
+
+  def testMergeBadEnumValue(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'optional_nested_enum: BARR'
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:23 : Enum type "protobuf_unittest.TestAllTypes.NestedEnum" '
+         'has no value named BARR.'),
+        text_format.Merge, text, message)
+
+    message = unittest_pb2.TestAllTypes()
+    text = 'optional_nested_enum: 100'
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:23 : Enum type "protobuf_unittest.TestAllTypes.NestedEnum" '
+         'has no value with number 100.'),
+        text_format.Merge, text, message)
+
+  def testMergeBadIntValue(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'optional_int32: bork'
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:17 : Couldn\'t parse integer: bork'),
+        text_format.Merge, text, message)
+
+  def testMergeStringFieldUnescape(self):
+    message = unittest_pb2.TestAllTypes()
+    text = r'''repeated_string: "\xf\x62"
+               repeated_string: "\\xf\\x62"
+               repeated_string: "\\\xf\\\x62"
+               repeated_string: "\\\\xf\\\\x62"
+               repeated_string: "\\\\\xf\\\\\x62"
+               repeated_string: "\x5cx20"'''
+    text_format.Merge(text, message)
+
+    SLASH = '\\'
+    self.assertEqual('\x0fb', message.repeated_string[0])
+    self.assertEqual(SLASH + 'xf' + SLASH + 'x62', message.repeated_string[1])
+    self.assertEqual(SLASH + '\x0f' + SLASH + 'b', message.repeated_string[2])
+    self.assertEqual(SLASH + SLASH + 'xf' + SLASH + SLASH + 'x62',
+                     message.repeated_string[3])
+    self.assertEqual(SLASH + SLASH + '\x0f' + SLASH + SLASH + 'b',
+                     message.repeated_string[4])
+    self.assertEqual(SLASH + 'x20', message.repeated_string[5])
+
+  def assertRaisesWithMessage(self, e_class, e, func, *args, **kwargs):
+    """Same as assertRaises, but also compares the exception message."""
+    if hasattr(e_class, '__name__'):
+      exc_name = e_class.__name__
+    else:
+      exc_name = str(e_class)
+
+    try:
+      func(*args, **kwargs)
+    except e_class as expr:
+      if str(expr) != e:
+        msg = '%s raised, but with wrong message: "%s" instead of "%s"'
+        raise self.failureException(msg % (exc_name,
+                                           str(expr).encode('string_escape'),
+                                           e.encode('string_escape')))
+      return
+    else:
+      raise self.failureException('%s not raised' % exc_name)
+
+
+class TokenizerTest(unittest.TestCase):
+  """
+  def testSimpleTokenCases(self):
+    text = ('identifier1:"string1"\n     \n\n'
+            'identifier2 : \n \n123  \n  identifier3 :\'string\'\n'
+            'identifiER_4 : 1.1e+2 ID5:-0.23 ID6:\'aaaa\\\'bbbb\'\n'
+            'ID7 : "aa\\"bb"\n\n\n\n ID8: {A:inf B:-inf C:true D:false}\n'
+            'ID9: 22 ID10: -111111111111111111 ID11: -22\n'
+            'ID12: 2222222222222222222 ID13: 1.23456f ID14: 1.2e+2f '
+            'false_bool:  0 true_BOOL:t \n true_bool1:  1 false_BOOL1:f ' )
+    tokenizer = text_format._Tokenizer(text)
+    methods = [(tokenizer.ConsumeIdentifier, 'identifier1'),
+               ':',
+               (tokenizer.ConsumeString, 'string1'),
+               (tokenizer.ConsumeIdentifier, 'identifier2'),
+               ':',
+               (tokenizer.ConsumeInt32, 123),
+               (tokenizer.ConsumeIdentifier, 'identifier3'),
+               ':',
+               (tokenizer.ConsumeString, 'string'),
+               (tokenizer.ConsumeIdentifier, 'identifiER_4'),
+               ':',
+               (tokenizer.ConsumeFloat, 1.1e+2),
+               (tokenizer.ConsumeIdentifier, 'ID5'),
+               ':',
+               (tokenizer.ConsumeFloat, -0.23),
+               (tokenizer.ConsumeIdentifier, 'ID6'),
+               ':',
+               (tokenizer.ConsumeString, 'aaaa\'bbbb'),
+               (tokenizer.ConsumeIdentifier, 'ID7'),
+               ':',
+               (tokenizer.ConsumeString, 'aa\"bb'),
+               (tokenizer.ConsumeIdentifier, 'ID8'),
+               ':',
+               '{',
+               (tokenizer.ConsumeIdentifier, 'A'),
+               ':',
+               (tokenizer.ConsumeFloat, float('inf')),
+               (tokenizer.ConsumeIdentifier, 'B'),
+               ':',
+               (tokenizer.ConsumeFloat, -float('inf')),
+               (tokenizer.ConsumeIdentifier, 'C'),
+               ':',
+               (tokenizer.ConsumeBool, True),
+               (tokenizer.ConsumeIdentifier, 'D'),
+               ':',
+               (tokenizer.ConsumeBool, False),
+               '}',
+               (tokenizer.ConsumeIdentifier, 'ID9'),
+               ':',
+               (tokenizer.ConsumeUint32, 22),
+               (tokenizer.ConsumeIdentifier, 'ID10'),
+               ':',
+               (tokenizer.ConsumeInt64, -111111111111111111),
+               (tokenizer.ConsumeIdentifier, 'ID11'),
+               ':',
+               (tokenizer.ConsumeInt32, -22),
+               (tokenizer.ConsumeIdentifier, 'ID12'),
+               ':',
+               (tokenizer.ConsumeUint64, 2222222222222222222),
+               (tokenizer.ConsumeIdentifier, 'ID13'),
+               ':',
+               (tokenizer.ConsumeFloat, 1.23456),
+               (tokenizer.ConsumeIdentifier, 'ID14'),
+               ':',
+               (tokenizer.ConsumeFloat, 1.2e+2),
+               (tokenizer.ConsumeIdentifier, 'false_bool'),
+               ':',
+               (tokenizer.ConsumeBool, False),
+               (tokenizer.ConsumeIdentifier, 'true_BOOL'),
+               ':',
+               (tokenizer.ConsumeBool, True),
+               (tokenizer.ConsumeIdentifier, 'true_bool1'),
+               ':',
+               (tokenizer.ConsumeBool, True),
+               (tokenizer.ConsumeIdentifier, 'false_BOOL1'),
+               ':',
+               (tokenizer.ConsumeBool, False)]
+
+    i = 0
+    while not tokenizer.AtEnd():
+      m = methods[i]
+      if type(m) == str:
+        token = tokenizer.token
+        self.assertEqual(token, m)
+        tokenizer.NextToken()
+      else:
+        self.assertEqual(m[1], m[0]())
+      i += 1
+
+  def testConsumeIntegers(self):
+    # This test only tests the failures in the integer parsing methods as well
+    # as the '0' special cases.
+    int64_max = (1 << 63) - 1
+    uint32_max = (1 << 32) - 1
+    text = '-1 %d %d' % (uint32_max + 1, int64_max + 1)
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeUint32)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeUint64)
+    self.assertEqual(-1, tokenizer.ConsumeInt32())
+
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeUint32)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeInt32)
+    self.assertEqual(uint32_max + 1, tokenizer.ConsumeInt64())
+
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeInt64)
+    self.assertEqual(int64_max + 1, tokenizer.ConsumeUint64())
+    self.assertTrue(tokenizer.AtEnd())
+
+    text = '-0 -0 0 0'
+    tokenizer = text_format._Tokenizer(text)
+    self.assertEqual(0, tokenizer.ConsumeUint32())
+    self.assertEqual(0, tokenizer.ConsumeUint64())
+    self.assertEqual(0, tokenizer.ConsumeUint32())
+    self.assertEqual(0, tokenizer.ConsumeUint64())
+    self.assertTrue(tokenizer.AtEnd())
+    """
+
+  def testConsumeByteString(self):
+    text = '"string1\''
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeByteString)
+
+    text = 'string1"'
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeByteString)
+
+    text = '\n"\\xt"'
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeByteString)
+
+    text = '\n"\\"'
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeByteString)
+
+    text = '\n"\\x"'
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeByteString)
+
+  def testConsumeBool(self):
+    text = 'not-a-bool'
+    tokenizer = text_format._Tokenizer(text)
+    self.assertRaises(text_format.ParseError, tokenizer.ConsumeBool)
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_unittest_data.txt b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_unittest_data.txt
new file mode 100644
index 0000000..bbe5882
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_unittest_data.txt
@@ -0,0 +1,128 @@
+optional_int32: 101
+optional_int64: 102
+optional_uint32: 103
+optional_uint64: 104
+optional_sint32: 105
+optional_sint64: 106
+optional_fixed32: 107
+optional_fixed64: 108
+optional_sfixed32: 109
+optional_sfixed64: 110
+optional_float: 111
+optional_double: 112
+optional_bool: true
+optional_string: "115"
+optional_bytes: "116"
+OptionalGroup {
+  a: 117
+}
+optional_nested_message {
+  bb: 118
+}
+optional_foreign_message {
+  c: 119
+}
+optional_import_message {
+  d: 120
+}
+optional_nested_enum: BAZ
+optional_foreign_enum: FOREIGN_BAZ
+optional_import_enum: IMPORT_BAZ
+optional_string_piece: "124"
+optional_cord: "125"
+optional_public_import_message {
+  e: 126
+}
+optional_lazy_message {
+  bb: 127
+}
+repeated_int32: 201
+repeated_int32: 301
+repeated_int64: 202
+repeated_int64: 302
+repeated_uint32: 203
+repeated_uint32: 303
+repeated_uint64: 204
+repeated_uint64: 304
+repeated_sint32: 205
+repeated_sint32: 305
+repeated_sint64: 206
+repeated_sint64: 306
+repeated_fixed32: 207
+repeated_fixed32: 307
+repeated_fixed64: 208
+repeated_fixed64: 308
+repeated_sfixed32: 209
+repeated_sfixed32: 309
+repeated_sfixed64: 210
+repeated_sfixed64: 310
+repeated_float: 211
+repeated_float: 311
+repeated_double: 212
+repeated_double: 312
+repeated_bool: true
+repeated_bool: false
+repeated_string: "215"
+repeated_string: "315"
+repeated_bytes: "216"
+repeated_bytes: "316"
+RepeatedGroup {
+  a: 217
+}
+RepeatedGroup {
+  a: 317
+}
+repeated_nested_message {
+  bb: 218
+}
+repeated_nested_message {
+  bb: 318
+}
+repeated_foreign_message {
+  c: 219
+}
+repeated_foreign_message {
+  c: 319
+}
+repeated_import_message {
+  d: 220
+}
+repeated_import_message {
+  d: 320
+}
+repeated_nested_enum: BAR
+repeated_nested_enum: BAZ
+repeated_foreign_enum: FOREIGN_BAR
+repeated_foreign_enum: FOREIGN_BAZ
+repeated_import_enum: IMPORT_BAR
+repeated_import_enum: IMPORT_BAZ
+repeated_string_piece: "224"
+repeated_string_piece: "324"
+repeated_cord: "225"
+repeated_cord: "325"
+repeated_lazy_message {
+  bb: 227
+}
+repeated_lazy_message {
+  bb: 327
+}
+default_int32: 401
+default_int64: 402
+default_uint32: 403
+default_uint64: 404
+default_sint32: 405
+default_sint64: 406
+default_fixed32: 407
+default_fixed64: 408
+default_sfixed32: 409
+default_sfixed64: 410
+default_float: 411
+default_double: 412
+default_bool: false
+default_string: "415"
+default_bytes: "416"
+default_nested_enum: FOO
+default_foreign_enum: FOREIGN_FOO
+default_import_enum: IMPORT_FOO
+default_string_piece: "424"
+default_cord: "425"
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_unittest_extensions_data.txt b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_unittest_extensions_data.txt
new file mode 100644
index 0000000..0a217f0
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/text_format_unittest_extensions_data.txt
@@ -0,0 +1,128 @@
+[protobuf_unittest.optional_int32_extension]: 101
+[protobuf_unittest.optional_int64_extension]: 102
+[protobuf_unittest.optional_uint32_extension]: 103
+[protobuf_unittest.optional_uint64_extension]: 104
+[protobuf_unittest.optional_sint32_extension]: 105
+[protobuf_unittest.optional_sint64_extension]: 106
+[protobuf_unittest.optional_fixed32_extension]: 107
+[protobuf_unittest.optional_fixed64_extension]: 108
+[protobuf_unittest.optional_sfixed32_extension]: 109
+[protobuf_unittest.optional_sfixed64_extension]: 110
+[protobuf_unittest.optional_float_extension]: 111
+[protobuf_unittest.optional_double_extension]: 112
+[protobuf_unittest.optional_bool_extension]: true
+[protobuf_unittest.optional_string_extension]: "115"
+[protobuf_unittest.optional_bytes_extension]: "116"
+[protobuf_unittest.optionalgroup_extension] {
+  a: 117
+}
+[protobuf_unittest.optional_nested_message_extension] {
+  bb: 118
+}
+[protobuf_unittest.optional_foreign_message_extension] {
+  c: 119
+}
+[protobuf_unittest.optional_import_message_extension] {
+  d: 120
+}
+[protobuf_unittest.optional_nested_enum_extension]: BAZ
+[protobuf_unittest.optional_foreign_enum_extension]: FOREIGN_BAZ
+[protobuf_unittest.optional_import_enum_extension]: IMPORT_BAZ
+[protobuf_unittest.optional_string_piece_extension]: "124"
+[protobuf_unittest.optional_cord_extension]: "125"
+[protobuf_unittest.optional_public_import_message_extension] {
+  e: 126
+}
+[protobuf_unittest.optional_lazy_message_extension] {
+  bb: 127
+}
+[protobuf_unittest.repeated_int32_extension]: 201
+[protobuf_unittest.repeated_int32_extension]: 301
+[protobuf_unittest.repeated_int64_extension]: 202
+[protobuf_unittest.repeated_int64_extension]: 302
+[protobuf_unittest.repeated_uint32_extension]: 203
+[protobuf_unittest.repeated_uint32_extension]: 303
+[protobuf_unittest.repeated_uint64_extension]: 204
+[protobuf_unittest.repeated_uint64_extension]: 304
+[protobuf_unittest.repeated_sint32_extension]: 205
+[protobuf_unittest.repeated_sint32_extension]: 305
+[protobuf_unittest.repeated_sint64_extension]: 206
+[protobuf_unittest.repeated_sint64_extension]: 306
+[protobuf_unittest.repeated_fixed32_extension]: 207
+[protobuf_unittest.repeated_fixed32_extension]: 307
+[protobuf_unittest.repeated_fixed64_extension]: 208
+[protobuf_unittest.repeated_fixed64_extension]: 308
+[protobuf_unittest.repeated_sfixed32_extension]: 209
+[protobuf_unittest.repeated_sfixed32_extension]: 309
+[protobuf_unittest.repeated_sfixed64_extension]: 210
+[protobuf_unittest.repeated_sfixed64_extension]: 310
+[protobuf_unittest.repeated_float_extension]: 211
+[protobuf_unittest.repeated_float_extension]: 311
+[protobuf_unittest.repeated_double_extension]: 212
+[protobuf_unittest.repeated_double_extension]: 312
+[protobuf_unittest.repeated_bool_extension]: true
+[protobuf_unittest.repeated_bool_extension]: false
+[protobuf_unittest.repeated_string_extension]: "215"
+[protobuf_unittest.repeated_string_extension]: "315"
+[protobuf_unittest.repeated_bytes_extension]: "216"
+[protobuf_unittest.repeated_bytes_extension]: "316"
+[protobuf_unittest.repeatedgroup_extension] {
+  a: 217
+}
+[protobuf_unittest.repeatedgroup_extension] {
+  a: 317
+}
+[protobuf_unittest.repeated_nested_message_extension] {
+  bb: 218
+}
+[protobuf_unittest.repeated_nested_message_extension] {
+  bb: 318
+}
+[protobuf_unittest.repeated_foreign_message_extension] {
+  c: 219
+}
+[protobuf_unittest.repeated_foreign_message_extension] {
+  c: 319
+}
+[protobuf_unittest.repeated_import_message_extension] {
+  d: 220
+}
+[protobuf_unittest.repeated_import_message_extension] {
+  d: 320
+}
+[protobuf_unittest.repeated_nested_enum_extension]: BAR
+[protobuf_unittest.repeated_nested_enum_extension]: BAZ
+[protobuf_unittest.repeated_foreign_enum_extension]: FOREIGN_BAR
+[protobuf_unittest.repeated_foreign_enum_extension]: FOREIGN_BAZ
+[protobuf_unittest.repeated_import_enum_extension]: IMPORT_BAR
+[protobuf_unittest.repeated_import_enum_extension]: IMPORT_BAZ
+[protobuf_unittest.repeated_string_piece_extension]: "224"
+[protobuf_unittest.repeated_string_piece_extension]: "324"
+[protobuf_unittest.repeated_cord_extension]: "225"
+[protobuf_unittest.repeated_cord_extension]: "325"
+[protobuf_unittest.repeated_lazy_message_extension] {
+  bb: 227
+}
+[protobuf_unittest.repeated_lazy_message_extension] {
+  bb: 327
+}
+[protobuf_unittest.default_int32_extension]: 401
+[protobuf_unittest.default_int64_extension]: 402
+[protobuf_unittest.default_uint32_extension]: 403
+[protobuf_unittest.default_uint64_extension]: 404
+[protobuf_unittest.default_sint32_extension]: 405
+[protobuf_unittest.default_sint64_extension]: 406
+[protobuf_unittest.default_fixed32_extension]: 407
+[protobuf_unittest.default_fixed64_extension]: 408
+[protobuf_unittest.default_sfixed32_extension]: 409
+[protobuf_unittest.default_sfixed64_extension]: 410
+[protobuf_unittest.default_float_extension]: 411
+[protobuf_unittest.default_double_extension]: 412
+[protobuf_unittest.default_bool_extension]: false
+[protobuf_unittest.default_string_extension]: "415"
+[protobuf_unittest.default_bytes_extension]: "416"
+[protobuf_unittest.default_nested_enum_extension]: FOO
+[protobuf_unittest.default_foreign_enum_extension]: FOREIGN_FOO
+[protobuf_unittest.default_import_enum_extension]: IMPORT_FOO
+[protobuf_unittest.default_string_piece_extension]: "424"
+[protobuf_unittest.default_cord_extension]: "425"
diff --git a/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/wire_format_test.py b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/wire_format_test.py
new file mode 100755
index 0000000..7600778
--- /dev/null
+++ b/python/compatibility_tests/v2.5.0/tests/google/protobuf/internal/wire_format_test.py
@@ -0,0 +1,253 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test for google.protobuf.internal.wire_format."""
+
+__author__ = 'robinson@google.com (Will Robinson)'
+
+import unittest
+from google.protobuf import message
+from google.protobuf.internal import wire_format
+
+
+class WireFormatTest(unittest.TestCase):
+
+  def testPackTag(self):
+    field_number = 0xabc
+    tag_type = 2
+    self.assertEqual((field_number << 3) | tag_type,
+                     wire_format.PackTag(field_number, tag_type))
+    PackTag = wire_format.PackTag
+    # Number too high.
+    self.assertRaises(message.EncodeError, PackTag, field_number, 6)
+    # Number too low.
+    self.assertRaises(message.EncodeError, PackTag, field_number, -1)
+
+  def testUnpackTag(self):
+    # Test field numbers that will require various varint sizes.
+    for expected_field_number in (1, 15, 16, 2047, 2048):
+      for expected_wire_type in range(6):  # Highest-numbered wiretype is 5.
+        field_number, wire_type = wire_format.UnpackTag(
+            wire_format.PackTag(expected_field_number, expected_wire_type))
+        self.assertEqual(expected_field_number, field_number)
+        self.assertEqual(expected_wire_type, wire_type)
+
+    self.assertRaises(TypeError, wire_format.UnpackTag, None)
+    self.assertRaises(TypeError, wire_format.UnpackTag, 'abc')
+    self.assertRaises(TypeError, wire_format.UnpackTag, 0.0)
+    self.assertRaises(TypeError, wire_format.UnpackTag, object())
+
+  def testZigZagEncode(self):
+    Z = wire_format.ZigZagEncode
+    self.assertEqual(0, Z(0))
+    self.assertEqual(1, Z(-1))
+    self.assertEqual(2, Z(1))
+    self.assertEqual(3, Z(-2))
+    self.assertEqual(4, Z(2))
+    self.assertEqual(0xfffffffe, Z(0x7fffffff))
+    self.assertEqual(0xffffffff, Z(-0x80000000))
+    self.assertEqual(0xfffffffffffffffe, Z(0x7fffffffffffffff))
+    self.assertEqual(0xffffffffffffffff, Z(-0x8000000000000000))
+
+    self.assertRaises(TypeError, Z, None)
+    self.assertRaises(TypeError, Z, 'abcd')
+    self.assertRaises(TypeError, Z, 0.0)
+    self.assertRaises(TypeError, Z, object())
+
+  def testZigZagDecode(self):
+    Z = wire_format.ZigZagDecode
+    self.assertEqual(0, Z(0))
+    self.assertEqual(-1, Z(1))
+    self.assertEqual(1, Z(2))
+    self.assertEqual(-2, Z(3))
+    self.assertEqual(2, Z(4))
+    self.assertEqual(0x7fffffff, Z(0xfffffffe))
+    self.assertEqual(-0x80000000, Z(0xffffffff))
+    self.assertEqual(0x7fffffffffffffff, Z(0xfffffffffffffffe))
+    self.assertEqual(-0x8000000000000000, Z(0xffffffffffffffff))
+
+    self.assertRaises(TypeError, Z, None)
+    self.assertRaises(TypeError, Z, 'abcd')
+    self.assertRaises(TypeError, Z, 0.0)
+    self.assertRaises(TypeError, Z, object())
+
+  def NumericByteSizeTestHelper(self, byte_size_fn, value, expected_value_size):
+    # Use field numbers that cause various byte sizes for the tag information.
+    for field_number, tag_bytes in ((15, 1), (16, 2), (2047, 2), (2048, 3)):
+      expected_size = expected_value_size + tag_bytes
+      actual_size = byte_size_fn(field_number, value)
+      self.assertEqual(expected_size, actual_size,
+                       'byte_size_fn: %s, field_number: %d, value: %r\n'
+                       'Expected: %d, Actual: %d'% (
+          byte_size_fn, field_number, value, expected_size, actual_size))
+
+  def testByteSizeFunctions(self):
+    # Test all numeric *ByteSize() functions.
+    NUMERIC_ARGS = [
+        # Int32ByteSize().
+        [wire_format.Int32ByteSize, 0, 1],
+        [wire_format.Int32ByteSize, 127, 1],
+        [wire_format.Int32ByteSize, 128, 2],
+        [wire_format.Int32ByteSize, -1, 10],
+        # Int64ByteSize().
+        [wire_format.Int64ByteSize, 0, 1],
+        [wire_format.Int64ByteSize, 127, 1],
+        [wire_format.Int64ByteSize, 128, 2],
+        [wire_format.Int64ByteSize, -1, 10],
+        # UInt32ByteSize().
+        [wire_format.UInt32ByteSize, 0, 1],
+        [wire_format.UInt32ByteSize, 127, 1],
+        [wire_format.UInt32ByteSize, 128, 2],
+        [wire_format.UInt32ByteSize, wire_format.UINT32_MAX, 5],
+        # UInt64ByteSize().
+        [wire_format.UInt64ByteSize, 0, 1],
+        [wire_format.UInt64ByteSize, 127, 1],
+        [wire_format.UInt64ByteSize, 128, 2],
+        [wire_format.UInt64ByteSize, wire_format.UINT64_MAX, 10],
+        # SInt32ByteSize().
+        [wire_format.SInt32ByteSize, 0, 1],
+        [wire_format.SInt32ByteSize, -1, 1],
+        [wire_format.SInt32ByteSize, 1, 1],
+        [wire_format.SInt32ByteSize, -63, 1],
+        [wire_format.SInt32ByteSize, 63, 1],
+        [wire_format.SInt32ByteSize, -64, 1],
+        [wire_format.SInt32ByteSize, 64, 2],
+        # SInt64ByteSize().
+        [wire_format.SInt64ByteSize, 0, 1],
+        [wire_format.SInt64ByteSize, -1, 1],
+        [wire_format.SInt64ByteSize, 1, 1],
+        [wire_format.SInt64ByteSize, -63, 1],
+        [wire_format.SInt64ByteSize, 63, 1],
+        [wire_format.SInt64ByteSize, -64, 1],
+        [wire_format.SInt64ByteSize, 64, 2],
+        # Fixed32ByteSize().
+        [wire_format.Fixed32ByteSize, 0, 4],
+        [wire_format.Fixed32ByteSize, wire_format.UINT32_MAX, 4],
+        # Fixed64ByteSize().
+        [wire_format.Fixed64ByteSize, 0, 8],
+        [wire_format.Fixed64ByteSize, wire_format.UINT64_MAX, 8],
+        # SFixed32ByteSize().
+        [wire_format.SFixed32ByteSize, 0, 4],
+        [wire_format.SFixed32ByteSize, wire_format.INT32_MIN, 4],
+        [wire_format.SFixed32ByteSize, wire_format.INT32_MAX, 4],
+        # SFixed64ByteSize().
+        [wire_format.SFixed64ByteSize, 0, 8],
+        [wire_format.SFixed64ByteSize, wire_format.INT64_MIN, 8],
+        [wire_format.SFixed64ByteSize, wire_format.INT64_MAX, 8],
+        # FloatByteSize().
+        [wire_format.FloatByteSize, 0.0, 4],
+        [wire_format.FloatByteSize, 1000000000.0, 4],
+        [wire_format.FloatByteSize, -1000000000.0, 4],
+        # DoubleByteSize().
+        [wire_format.DoubleByteSize, 0.0, 8],
+        [wire_format.DoubleByteSize, 1000000000.0, 8],
+        [wire_format.DoubleByteSize, -1000000000.0, 8],
+        # BoolByteSize().
+        [wire_format.BoolByteSize, False, 1],
+        [wire_format.BoolByteSize, True, 1],
+        # EnumByteSize().
+        [wire_format.EnumByteSize, 0, 1],
+        [wire_format.EnumByteSize, 127, 1],
+        [wire_format.EnumByteSize, 128, 2],
+        [wire_format.EnumByteSize, wire_format.UINT32_MAX, 5],
+        ]
+    for args in NUMERIC_ARGS:
+      self.NumericByteSizeTestHelper(*args)
+
+    # Test strings and bytes.
+    for byte_size_fn in (wire_format.StringByteSize, wire_format.BytesByteSize):
+      # 1 byte for tag, 1 byte for length, 3 bytes for contents.
+      self.assertEqual(5, byte_size_fn(10, 'abc'))
+      # 2 bytes for tag, 1 byte for length, 3 bytes for contents.
+      self.assertEqual(6, byte_size_fn(16, 'abc'))
+      # 2 bytes for tag, 2 bytes for length, 128 bytes for contents.
+      self.assertEqual(132, byte_size_fn(16, 'a' * 128))
+
+    # Test UTF-8 string byte size calculation.
+    # 1 byte for tag, 1 byte for length, 8 bytes for content.
+    self.assertEqual(10, wire_format.StringByteSize(
+        5, unicode('\xd0\xa2\xd0\xb5\xd1\x81\xd1\x82', 'utf-8')))
+
+    class MockMessage(object):
+      def __init__(self, byte_size):
+        self.byte_size = byte_size
+      def ByteSize(self):
+        return self.byte_size
+
+    message_byte_size = 10
+    mock_message = MockMessage(byte_size=message_byte_size)
+    # Test groups.
+    # (2 * 1) bytes for begin and end tags, plus message_byte_size.
+    self.assertEqual(2 + message_byte_size,
+                     wire_format.GroupByteSize(1, mock_message))
+    # (2 * 2) bytes for begin and end tags, plus message_byte_size.
+    self.assertEqual(4 + message_byte_size,
+                     wire_format.GroupByteSize(16, mock_message))
+
+    # Test messages.
+    # 1 byte for tag, plus 1 byte for length, plus contents.
+    self.assertEqual(2 + mock_message.byte_size,
+                     wire_format.MessageByteSize(1, mock_message))
+    # 2 bytes for tag, plus 1 byte for length, plus contents.
+    self.assertEqual(3 + mock_message.byte_size,
+                     wire_format.MessageByteSize(16, mock_message))
+    # 2 bytes for tag, plus 2 bytes for length, plus contents.
+    mock_message.byte_size = 128
+    self.assertEqual(4 + mock_message.byte_size,
+                     wire_format.MessageByteSize(16, mock_message))
+
+
+    # Test message set item byte size.
+    # 4 bytes for tags, plus 1 byte for length, plus 1 byte for type_id,
+    # plus contents.
+    mock_message.byte_size = 10
+    self.assertEqual(mock_message.byte_size + 6,
+                     wire_format.MessageSetItemByteSize(1, mock_message))
+
+    # 4 bytes for tags, plus 2 bytes for length, plus 1 byte for type_id,
+    # plus contents.
+    mock_message.byte_size = 128
+    self.assertEqual(mock_message.byte_size + 7,
+                     wire_format.MessageSetItemByteSize(1, mock_message))
+
+    # 4 bytes for tags, plus 2 bytes for length, plus 2 byte for type_id,
+    # plus contents.
+    self.assertEqual(mock_message.byte_size + 8,
+                     wire_format.MessageSetItemByteSize(128, mock_message))
+
+    # Too-long varint.
+    self.assertRaises(message.EncodeError,
+                      wire_format.UInt64ByteSize, 1, 1 << 128)
+
+
+if __name__ == '__main__':
+  unittest.main()