diff --git a/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs b/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs
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+++ b/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs
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+#region Copyright notice and license
+// 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.
+#endregion
+
+using System;
+using System.IO;
+using Google.Protobuf.TestProtos;
+using NUnit.Framework;
+
+namespace Google.Protobuf
+{
+    public class CodedOutputStreamTest
+    {
+        /// <summary>
+        /// Writes the given value using WriteRawVarint32() and WriteRawVarint64() and
+        /// checks that the result matches the given bytes
+        /// </summary>
+        private static void AssertWriteVarint(byte[] data, ulong value)
+        {
+            // Only do 32-bit write if the value fits in 32 bits.
+            if ((value >> 32) == 0)
+            {
+                MemoryStream rawOutput = new MemoryStream();
+                CodedOutputStream output = new CodedOutputStream(rawOutput);
+                output.WriteRawVarint32((uint) value);
+                output.Flush();
+                Assert.AreEqual(data, rawOutput.ToArray());
+                // Also try computing size.
+                Assert.AreEqual(data.Length, CodedOutputStream.ComputeRawVarint32Size((uint) value));
+            }
+
+            {
+                MemoryStream rawOutput = new MemoryStream();
+                CodedOutputStream output = new CodedOutputStream(rawOutput);
+                output.WriteRawVarint64(value);
+                output.Flush();
+                Assert.AreEqual(data, rawOutput.ToArray());
+
+                // Also try computing size.
+                Assert.AreEqual(data.Length, CodedOutputStream.ComputeRawVarint64Size(value));
+            }
+
+            // Try different buffer sizes.
+            for (int bufferSize = 1; bufferSize <= 16; bufferSize *= 2)
+            {
+                // Only do 32-bit write if the value fits in 32 bits.
+                if ((value >> 32) == 0)
+                {
+                    MemoryStream rawOutput = new MemoryStream();
+                    CodedOutputStream output =
+                        new CodedOutputStream(rawOutput, bufferSize);
+                    output.WriteRawVarint32((uint) value);
+                    output.Flush();
+                    Assert.AreEqual(data, rawOutput.ToArray());
+                }
+
+                {
+                    MemoryStream rawOutput = new MemoryStream();
+                    CodedOutputStream output = new CodedOutputStream(rawOutput, bufferSize);
+                    output.WriteRawVarint64(value);
+                    output.Flush();
+                    Assert.AreEqual(data, rawOutput.ToArray());
+                }
+            }
+        }
+
+        /// <summary>
+        /// Tests WriteRawVarint32() and WriteRawVarint64()
+        /// </summary>
+        [Test]
+        public void WriteVarint()
+        {
+            AssertWriteVarint(new byte[] {0x00}, 0);
+            AssertWriteVarint(new byte[] {0x01}, 1);
+            AssertWriteVarint(new byte[] {0x7f}, 127);
+            // 14882
+            AssertWriteVarint(new byte[] {0xa2, 0x74}, (0x22 << 0) | (0x74 << 7));
+            // 2961488830
+            AssertWriteVarint(new byte[] {0xbe, 0xf7, 0x92, 0x84, 0x0b},
+                              (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
+                              (0x0bL << 28));
+
+            // 64-bit
+            // 7256456126
+            AssertWriteVarint(new byte[] {0xbe, 0xf7, 0x92, 0x84, 0x1b},
+                              (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
+                              (0x1bL << 28));
+            // 41256202580718336
+            AssertWriteVarint(
+                new byte[] {0x80, 0xe6, 0xeb, 0x9c, 0xc3, 0xc9, 0xa4, 0x49},
+                (0x00 << 0) | (0x66 << 7) | (0x6b << 14) | (0x1c << 21) |
+                (0x43UL << 28) | (0x49L << 35) | (0x24UL << 42) | (0x49UL << 49));
+            // 11964378330978735131
+            AssertWriteVarint(
+                new byte[] {0x9b, 0xa8, 0xf9, 0xc2, 0xbb, 0xd6, 0x80, 0x85, 0xa6, 0x01},
+                unchecked((ulong)
+                          ((0x1b << 0) | (0x28 << 7) | (0x79 << 14) | (0x42 << 21) |
+                           (0x3bL << 28) | (0x56L << 35) | (0x00L << 42) |
+                           (0x05L << 49) | (0x26L << 56) | (0x01L << 63))));
+        }
+
+        /// <summary>
+        /// Parses the given bytes using WriteRawLittleEndian32() and checks
+        /// that the result matches the given value.
+        /// </summary>
+        private static void AssertWriteLittleEndian32(byte[] data, uint value)
+        {
+            MemoryStream rawOutput = new MemoryStream();
+            CodedOutputStream output = new CodedOutputStream(rawOutput);
+            output.WriteRawLittleEndian32(value);
+            output.Flush();
+            Assert.AreEqual(data, rawOutput.ToArray());
+
+            // Try different buffer sizes.
+            for (int bufferSize = 1; bufferSize <= 16; bufferSize *= 2)
+            {
+                rawOutput = new MemoryStream();
+                output = new CodedOutputStream(rawOutput, bufferSize);
+                output.WriteRawLittleEndian32(value);
+                output.Flush();
+                Assert.AreEqual(data, rawOutput.ToArray());
+            }
+        }
+
+        /// <summary>
+        /// Parses the given bytes using WriteRawLittleEndian64() and checks
+        /// that the result matches the given value.
+        /// </summary>
+        private static void AssertWriteLittleEndian64(byte[] data, ulong value)
+        {
+            MemoryStream rawOutput = new MemoryStream();
+            CodedOutputStream output = new CodedOutputStream(rawOutput);
+            output.WriteRawLittleEndian64(value);
+            output.Flush();
+            Assert.AreEqual(data, rawOutput.ToArray());
+
+            // Try different block sizes.
+            for (int blockSize = 1; blockSize <= 16; blockSize *= 2)
+            {
+                rawOutput = new MemoryStream();
+                output = new CodedOutputStream(rawOutput, blockSize);
+                output.WriteRawLittleEndian64(value);
+                output.Flush();
+                Assert.AreEqual(data, rawOutput.ToArray());
+            }
+        }
+
+        /// <summary>
+        /// Tests writeRawLittleEndian32() and writeRawLittleEndian64().
+        /// </summary>
+        [Test]
+        public void WriteLittleEndian()
+        {
+            AssertWriteLittleEndian32(new byte[] {0x78, 0x56, 0x34, 0x12}, 0x12345678);
+            AssertWriteLittleEndian32(new byte[] {0xf0, 0xde, 0xbc, 0x9a}, 0x9abcdef0);
+
+            AssertWriteLittleEndian64(
+                new byte[] {0xf0, 0xde, 0xbc, 0x9a, 0x78, 0x56, 0x34, 0x12},
+                0x123456789abcdef0L);
+            AssertWriteLittleEndian64(
+                new byte[] {0x78, 0x56, 0x34, 0x12, 0xf0, 0xde, 0xbc, 0x9a},
+                0x9abcdef012345678UL);
+        }
+
+        [Test]
+        public void WriteWholeMessage_VaryingBlockSizes()
+        {
+            TestAllTypes message = SampleMessages.CreateFullTestAllTypes();
+
+            byte[] rawBytes = message.ToByteArray();
+
+            // Try different block sizes.
+            for (int blockSize = 1; blockSize < 256; blockSize *= 2)
+            {
+                MemoryStream rawOutput = new MemoryStream();
+                CodedOutputStream output = new CodedOutputStream(rawOutput, blockSize);
+                message.WriteTo(output);
+                output.Flush();
+                Assert.AreEqual(rawBytes, rawOutput.ToArray());
+            }
+        }
+        
+        [Test]
+        public void EncodeZigZag32()
+        {
+            Assert.AreEqual(0u, CodedOutputStream.EncodeZigZag32(0));
+            Assert.AreEqual(1u, CodedOutputStream.EncodeZigZag32(-1));
+            Assert.AreEqual(2u, CodedOutputStream.EncodeZigZag32(1));
+            Assert.AreEqual(3u, CodedOutputStream.EncodeZigZag32(-2));
+            Assert.AreEqual(0x7FFFFFFEu, CodedOutputStream.EncodeZigZag32(0x3FFFFFFF));
+            Assert.AreEqual(0x7FFFFFFFu, CodedOutputStream.EncodeZigZag32(unchecked((int) 0xC0000000)));
+            Assert.AreEqual(0xFFFFFFFEu, CodedOutputStream.EncodeZigZag32(0x7FFFFFFF));
+            Assert.AreEqual(0xFFFFFFFFu, CodedOutputStream.EncodeZigZag32(unchecked((int) 0x80000000)));
+        }
+
+        [Test]
+        public void EncodeZigZag64()
+        {
+            Assert.AreEqual(0u, CodedOutputStream.EncodeZigZag64(0));
+            Assert.AreEqual(1u, CodedOutputStream.EncodeZigZag64(-1));
+            Assert.AreEqual(2u, CodedOutputStream.EncodeZigZag64(1));
+            Assert.AreEqual(3u, CodedOutputStream.EncodeZigZag64(-2));
+            Assert.AreEqual(0x000000007FFFFFFEuL,
+                            CodedOutputStream.EncodeZigZag64(unchecked((long) 0x000000003FFFFFFFUL)));
+            Assert.AreEqual(0x000000007FFFFFFFuL,
+                            CodedOutputStream.EncodeZigZag64(unchecked((long) 0xFFFFFFFFC0000000UL)));
+            Assert.AreEqual(0x00000000FFFFFFFEuL,
+                            CodedOutputStream.EncodeZigZag64(unchecked((long) 0x000000007FFFFFFFUL)));
+            Assert.AreEqual(0x00000000FFFFFFFFuL,
+                            CodedOutputStream.EncodeZigZag64(unchecked((long) 0xFFFFFFFF80000000UL)));
+            Assert.AreEqual(0xFFFFFFFFFFFFFFFEL,
+                            CodedOutputStream.EncodeZigZag64(unchecked((long) 0x7FFFFFFFFFFFFFFFUL)));
+            Assert.AreEqual(0xFFFFFFFFFFFFFFFFL,
+                            CodedOutputStream.EncodeZigZag64(unchecked((long) 0x8000000000000000UL)));
+        }
+
+        [Test]
+        public void RoundTripZigZag32()
+        {
+            // Some easier-to-verify round-trip tests.  The inputs (other than 0, 1, -1)
+            // were chosen semi-randomly via keyboard bashing.
+            Assert.AreEqual(0, CodedInputStream.DecodeZigZag32(CodedOutputStream.EncodeZigZag32(0)));
+            Assert.AreEqual(1, CodedInputStream.DecodeZigZag32(CodedOutputStream.EncodeZigZag32(1)));
+            Assert.AreEqual(-1, CodedInputStream.DecodeZigZag32(CodedOutputStream.EncodeZigZag32(-1)));
+            Assert.AreEqual(14927, CodedInputStream.DecodeZigZag32(CodedOutputStream.EncodeZigZag32(14927)));
+            Assert.AreEqual(-3612, CodedInputStream.DecodeZigZag32(CodedOutputStream.EncodeZigZag32(-3612)));
+        }
+
+        [Test]
+        public void RoundTripZigZag64()
+        {
+            Assert.AreEqual(0, CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(0)));
+            Assert.AreEqual(1, CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(1)));
+            Assert.AreEqual(-1, CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(-1)));
+            Assert.AreEqual(14927, CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(14927)));
+            Assert.AreEqual(-3612, CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(-3612)));
+
+            Assert.AreEqual(856912304801416L,
+                            CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(856912304801416L)));
+            Assert.AreEqual(-75123905439571256L,
+                            CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(-75123905439571256L)));
+        }
+
+        [Test]
+        public void TestNegativeEnumNoTag()
+        {
+            Assert.AreEqual(10, CodedOutputStream.ComputeInt32Size(-2));
+            Assert.AreEqual(10, CodedOutputStream.ComputeEnumSize((int) SampleEnum.NegativeValue));
+
+            byte[] bytes = new byte[10];
+            CodedOutputStream output = new CodedOutputStream(bytes);
+            output.WriteEnum((int) SampleEnum.NegativeValue);
+
+            Assert.AreEqual(0, output.SpaceLeft);
+            Assert.AreEqual("FE-FF-FF-FF-FF-FF-FF-FF-FF-01", BitConverter.ToString(bytes));
+        }
+
+        [Test]
+        public void TestCodedInputOutputPosition()
+        {
+            byte[] content = new byte[110];
+            for (int i = 0; i < content.Length; i++)
+                content[i] = (byte)i;
+
+            byte[] child = new byte[120];
+            {
+                MemoryStream ms = new MemoryStream(child);
+                CodedOutputStream cout = new CodedOutputStream(ms, 20);
+                // Field 11: numeric value: 500
+                cout.WriteTag(11, WireFormat.WireType.Varint);
+                Assert.AreEqual(1, cout.Position);
+                cout.WriteInt32(500);
+                Assert.AreEqual(3, cout.Position);
+                //Field 12: length delimited 120 bytes
+                cout.WriteTag(12, WireFormat.WireType.LengthDelimited);
+                Assert.AreEqual(4, cout.Position);
+                cout.WriteBytes(ByteString.CopyFrom(content));
+                Assert.AreEqual(115, cout.Position);
+                // Field 13: fixed numeric value: 501
+                cout.WriteTag(13, WireFormat.WireType.Fixed32);
+                Assert.AreEqual(116, cout.Position);
+                cout.WriteSFixed32(501);
+                Assert.AreEqual(120, cout.Position);
+                cout.Flush();
+            }
+
+            byte[] bytes = new byte[130];
+            {
+                CodedOutputStream cout = new CodedOutputStream(bytes);
+                // Field 1: numeric value: 500
+                cout.WriteTag(1, WireFormat.WireType.Varint);
+                Assert.AreEqual(1, cout.Position);
+                cout.WriteInt32(500);
+                Assert.AreEqual(3, cout.Position);
+                //Field 2: length delimited 120 bytes
+                cout.WriteTag(2, WireFormat.WireType.LengthDelimited);
+                Assert.AreEqual(4, cout.Position);
+                cout.WriteBytes(ByteString.CopyFrom(child));
+                Assert.AreEqual(125, cout.Position);
+                // Field 3: fixed numeric value: 500
+                cout.WriteTag(3, WireFormat.WireType.Fixed32);
+                Assert.AreEqual(126, cout.Position);
+                cout.WriteSFixed32(501);
+                Assert.AreEqual(130, cout.Position);
+                cout.Flush();
+            }
+            // Now test Input stream:
+            {
+                CodedInputStream cin = new CodedInputStream(new MemoryStream(bytes), new byte[50], 0, 0);
+                Assert.AreEqual(0, cin.Position);
+                // Field 1:
+                uint tag = cin.ReadTag();
+                Assert.AreEqual(1, tag >> 3);
+                Assert.AreEqual(1, cin.Position);
+                Assert.AreEqual(500, cin.ReadInt32());
+                Assert.AreEqual(3, cin.Position);
+                //Field 2:
+                tag = cin.ReadTag();
+                Assert.AreEqual(2, tag >> 3);
+                Assert.AreEqual(4, cin.Position);
+                int childlen = cin.ReadLength();
+                Assert.AreEqual(120, childlen);
+                Assert.AreEqual(5, cin.Position);
+                int oldlimit = cin.PushLimit((int)childlen);
+                Assert.AreEqual(5, cin.Position);
+                // Now we are reading child message
+                {
+                    // Field 11: numeric value: 500
+                    tag = cin.ReadTag();
+                    Assert.AreEqual(11, tag >> 3);
+                    Assert.AreEqual(6, cin.Position);
+                    Assert.AreEqual(500, cin.ReadInt32());
+                    Assert.AreEqual(8, cin.Position);
+                    //Field 12: length delimited 120 bytes
+                    tag = cin.ReadTag();
+                    Assert.AreEqual(12, tag >> 3);
+                    Assert.AreEqual(9, cin.Position);
+                    ByteString bstr = cin.ReadBytes();
+                    Assert.AreEqual(110, bstr.Length);
+                    Assert.AreEqual((byte) 109, bstr[109]);
+                    Assert.AreEqual(120, cin.Position);
+                    // Field 13: fixed numeric value: 501
+                    tag = cin.ReadTag();
+                    Assert.AreEqual(13, tag >> 3);
+                    // ROK - Previously broken here, this returned 126 failing to account for bufferSizeAfterLimit
+                    Assert.AreEqual(121, cin.Position);
+                    Assert.AreEqual(501, cin.ReadSFixed32());
+                    Assert.AreEqual(125, cin.Position);
+                    Assert.IsTrue(cin.IsAtEnd);
+                }
+                cin.PopLimit(oldlimit);
+                Assert.AreEqual(125, cin.Position);
+                // Field 3: fixed numeric value: 501
+                tag = cin.ReadTag();
+                Assert.AreEqual(3, tag >> 3);
+                Assert.AreEqual(126, cin.Position);
+                Assert.AreEqual(501, cin.ReadSFixed32());
+                Assert.AreEqual(130, cin.Position);
+                Assert.IsTrue(cin.IsAtEnd);
+            }
+        }
+    }
+}
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