diff --git a/objectivec/DevTools/pddm_tests.py b/objectivec/DevTools/pddm_tests.py
new file mode 100755
index 0000000..8a73b84
--- /dev/null
+++ b/objectivec/DevTools/pddm_tests.py
@@ -0,0 +1,515 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2015 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.
+
+"""Tests for pddm.py."""
+
+import io
+import unittest
+
+import pddm
+
+
+class TestParsingMacros(unittest.TestCase):
+
+  def testParseEmpty(self):
+    f = io.StringIO(u'')
+    result = pddm.MacroCollection(f)
+    self.assertEqual(len(result._macros), 0)
+
+  def testParseOne(self):
+    f = io.StringIO(u"""PDDM-DEFINE foo( )
+body""")
+    result = pddm.MacroCollection(f)
+    self.assertEqual(len(result._macros), 1)
+    macro = result._macros.get('foo')
+    self.assertIsNotNone(macro)
+    self.assertEquals(macro.name, 'foo')
+    self.assertEquals(macro.args, tuple())
+    self.assertEquals(macro.body, 'body')
+
+  def testParseGeneral(self):
+    # Tests multiple defines, spaces in all places, etc.
+    f = io.StringIO(u"""
+PDDM-DEFINE noArgs( )
+body1
+body2
+
+PDDM-DEFINE-END
+
+PDDM-DEFINE oneArg(foo)
+body3
+PDDM-DEFINE  twoArgs( bar_ , baz )
+body4
+body5""")
+    result = pddm.MacroCollection(f)
+    self.assertEqual(len(result._macros), 3)
+    macro = result._macros.get('noArgs')
+    self.assertIsNotNone(macro)
+    self.assertEquals(macro.name, 'noArgs')
+    self.assertEquals(macro.args, tuple())
+    self.assertEquals(macro.body, 'body1\nbody2\n')
+    macro = result._macros.get('oneArg')
+    self.assertIsNotNone(macro)
+    self.assertEquals(macro.name, 'oneArg')
+    self.assertEquals(macro.args, ('foo',))
+    self.assertEquals(macro.body, 'body3')
+    macro = result._macros.get('twoArgs')
+    self.assertIsNotNone(macro)
+    self.assertEquals(macro.name, 'twoArgs')
+    self.assertEquals(macro.args, ('bar_', 'baz'))
+    self.assertEquals(macro.body, 'body4\nbody5')
+    # Add into existing collection
+    f = io.StringIO(u"""
+PDDM-DEFINE another(a,b,c)
+body1
+body2""")
+    result.ParseInput(f)
+    self.assertEqual(len(result._macros), 4)
+    macro = result._macros.get('another')
+    self.assertIsNotNone(macro)
+    self.assertEquals(macro.name, 'another')
+    self.assertEquals(macro.args, ('a', 'b', 'c'))
+    self.assertEquals(macro.body, 'body1\nbody2')
+
+  def testParseDirectiveIssues(self):
+    test_list = [
+      # Unknown directive
+      (u'PDDM-DEFINE foo()\nbody\nPDDM-DEFINED foo\nbaz',
+       'Hit a line with an unknown directive: '),
+      # End without begin
+      (u'PDDM-DEFINE foo()\nbody\nPDDM-DEFINE-END\nPDDM-DEFINE-END\n',
+       'Got DEFINE-END directive without an active macro: '),
+      # Line not in macro block
+      (u'PDDM-DEFINE foo()\nbody\nPDDM-DEFINE-END\nmumble\n',
+       'Hit a line that wasn\'t a directive and no open macro definition: '),
+      # Redefine macro
+      (u'PDDM-DEFINE foo()\nbody\nPDDM-DEFINE foo(a)\nmumble\n',
+       'Attempt to redefine macro: '),
+    ]
+    for idx, (input_str, expected_prefix) in enumerate(test_list, 1):
+      f = io.StringIO(input_str)
+      try:
+        result = pddm.MacroCollection(f)
+        self.fail('Should throw exception, entry %d' % idx)
+      except pddm.PDDMError as e:
+        self.assertTrue(e.message.startswith(expected_prefix),
+                        'Entry %d failed: %r' % (idx, e))
+
+  def testParseBeginIssues(self):
+    test_list = [
+      # 1. No name
+      (u'PDDM-DEFINE\nmumble',
+       'Failed to parse macro definition: '),
+      # 2. No name (with spaces)
+      (u'PDDM-DEFINE  \nmumble',
+       'Failed to parse macro definition: '),
+      # 3. No open paren
+      (u'PDDM-DEFINE  foo\nmumble',
+       'Failed to parse macro definition: '),
+      # 4. No close paren
+      (u'PDDM-DEFINE foo(\nmumble',
+       'Failed to parse macro definition: '),
+      # 5. No close paren (with args)
+      (u'PDDM-DEFINE foo(a, b\nmumble',
+       'Failed to parse macro definition: '),
+      # 6. No name before args
+      (u'PDDM-DEFINE  (a, b)\nmumble',
+       'Failed to parse macro definition: '),
+      # 7. No name before args
+      (u'PDDM-DEFINE foo bar(a, b)\nmumble',
+       'Failed to parse macro definition: '),
+      # 8. Empty arg name
+      (u'PDDM-DEFINE foo(a, ,b)\nmumble',
+       'Empty arg name in macro definition: '),
+      (u'PDDM-DEFINE foo(a,,b)\nmumble',
+       'Empty arg name in macro definition: '),
+      # 10. Duplicate name
+      (u'PDDM-DEFINE foo(a,b,a,c)\nmumble',
+       'Arg name "a" used more than once in macro definition: '),
+      # 11. Invalid arg name
+      (u'PDDM-DEFINE foo(a b,c)\nmumble',
+       'Invalid arg name "a b" in macro definition: '),
+      (u'PDDM-DEFINE foo(a.b,c)\nmumble',
+       'Invalid arg name "a.b" in macro definition: '),
+      (u'PDDM-DEFINE foo(a-b,c)\nmumble',
+       'Invalid arg name "a-b" in macro definition: '),
+      (u'PDDM-DEFINE foo(a,b,c.)\nmumble',
+       'Invalid arg name "c." in macro definition: '),
+      # 15. Extra stuff after the name
+      (u'PDDM-DEFINE foo(a,c) foo\nmumble',
+       'Failed to parse macro definition: '),
+      (u'PDDM-DEFINE foo(a,c) foo)\nmumble',
+       'Failed to parse macro definition: '),
+    ]
+    for idx, (input_str, expected_prefix) in enumerate(test_list, 1):
+      f = io.StringIO(input_str)
+      try:
+        result = pddm.MacroCollection(f)
+        self.fail('Should throw exception, entry %d' % idx)
+      except pddm.PDDMError as e:
+        self.assertTrue(e.message.startswith(expected_prefix),
+                        'Entry %d failed: %r' % (idx, e))
+
+
+class TestExpandingMacros(unittest.TestCase):
+
+  def testExpandBasics(self):
+    f = io.StringIO(u"""
+PDDM-DEFINE noArgs( )
+body1
+body2
+
+PDDM-DEFINE-END
+
+PDDM-DEFINE oneArg(a)
+body3 a
+
+PDDM-DEFINE-END
+
+PDDM-DEFINE twoArgs(b,c)
+body4 b c
+body5
+PDDM-DEFINE-END
+
+""")
+    mc = pddm.MacroCollection(f)
+    test_list = [
+      (u'noArgs()',
+       'body1\nbody2\n'),
+      (u'oneArg(wee)',
+       'body3 wee\n'),
+      (u'twoArgs(having some, fun)',
+       'body4 having some fun\nbody5'),
+      # One arg, pass empty.
+      (u'oneArg()',
+       'body3 \n'),
+      # Two args, gets empty in each slot.
+      (u'twoArgs(, empty)',
+       'body4  empty\nbody5'),
+      (u'twoArgs(empty, )',
+       'body4 empty \nbody5'),
+      (u'twoArgs(, )',
+       'body4  \nbody5'),
+    ]
+    for idx, (input_str, expected) in enumerate(test_list, 1):
+      result = mc.Expand(input_str)
+      self.assertEqual(result, expected,
+                       'Entry %d --\n       Result: %r\n     Expected: %r' %
+                       (idx, result, expected))
+
+  def testExpandArgOptions(self):
+    f = io.StringIO(u"""
+PDDM-DEFINE bar(a)
+a-a$S-a$l-a$L-a$u-a$U
+PDDM-DEFINE-END
+""")
+    mc = pddm.MacroCollection(f)
+
+    self.assertEqual(mc.Expand('bar(xYz)'), 'xYz-   -xYz-xyz-XYz-XYZ')
+    self.assertEqual(mc.Expand('bar(MnoP)'), 'MnoP-    -mnoP-mnop-MnoP-MNOP')
+    # Test empty
+    self.assertEqual(mc.Expand('bar()'), '-----')
+
+  def testExpandSimpleMacroErrors(self):
+    f = io.StringIO(u"""
+PDDM-DEFINE foo(a, b)
+<a-z>
+PDDM-DEFINE baz(a)
+a - a$z
+""")
+    mc = pddm.MacroCollection(f)
+    test_list = [
+      # 1. Unknown macro
+      (u'bar()',
+       'No macro named "bar".'),
+      (u'bar(a)',
+       'No macro named "bar".'),
+      # 3. Arg mismatch
+      (u'foo()',
+       'Expected 2 args, got: "foo()".'),
+      (u'foo(a b)',
+       'Expected 2 args, got: "foo(a b)".'),
+      (u'foo(a,b,c)',
+       'Expected 2 args, got: "foo(a,b,c)".'),
+      # 6. Unknown option in expansion
+      (u'baz(mumble)',
+       'Unknown arg option "a$z" while expanding "baz(mumble)".'),
+    ]
+    for idx, (input_str, expected_err) in enumerate(test_list, 1):
+      try:
+        result = mc.Expand(input_str)
+        self.fail('Should throw exception, entry %d' % idx)
+      except pddm.PDDMError as e:
+        self.assertEqual(e.message, expected_err,
+                        'Entry %d failed: %r' % (idx, e))
+
+  def testExpandReferences(self):
+    f = io.StringIO(u"""
+PDDM-DEFINE StartIt()
+foo(abc, def)
+foo(ghi, jkl)
+PDDM-DEFINE foo(a, b)
+bar(a, int)
+bar(b, NSString *)
+PDDM-DEFINE bar(n, t)
+- (t)n;
+- (void)set##n$u##:(t)value;
+
+""")
+    mc = pddm.MacroCollection(f)
+    expected = """- (int)abc;
+- (void)setAbc:(int)value;
+
+- (NSString *)def;
+- (void)setDef:(NSString *)value;
+
+- (int)ghi;
+- (void)setGhi:(int)value;
+
+- (NSString *)jkl;
+- (void)setJkl:(NSString *)value;
+"""
+    self.assertEqual(mc.Expand('StartIt()'), expected)
+
+  def testCatchRecursion(self):
+    f = io.StringIO(u"""
+PDDM-DEFINE foo(a, b)
+bar(1, a)
+bar(2, b)
+PDDM-DEFINE bar(x, y)
+foo(x, y)
+""")
+    mc = pddm.MacroCollection(f)
+    try:
+      result = mc.Expand('foo(A,B)')
+      self.fail('Should throw exception, entry %d' % idx)
+    except pddm.PDDMError as e:
+      self.assertEqual(e.message,
+                       'Found macro recusion, invoking "foo(1, A)":\n...while expanding "bar(1, A)".\n...while expanding "foo(A,B)".')
+
+
+class TestParsingSource(unittest.TestCase):
+
+  def testBasicParse(self):
+    test_list = [
+      # 1. no directives
+      (u'a\nb\nc',
+       (3,) ),
+      # 2. One define
+      (u'a\n//%PDDM-DEFINE foo()\n//%body\nc',
+       (1, 2, 1) ),
+      # 3. Two defines
+      (u'a\n//%PDDM-DEFINE foo()\n//%body\n//%PDDM-DEFINE bar()\n//%body2\nc',
+       (1, 4, 1) ),
+      # 4. Two defines with ends
+      (u'a\n//%PDDM-DEFINE foo()\n//%body\n//%PDDM-DEFINE-END\n'
+       u'//%PDDM-DEFINE bar()\n//%body2\n//%PDDM-DEFINE-END\nc',
+       (1, 6, 1) ),
+      # 5. One expand, one define (that runs to end of file)
+      (u'a\n//%PDDM-EXPAND foo()\nbody\n//%PDDM-EXPAND-END\n'
+       u'//%PDDM-DEFINE bar()\n//%body2\n',
+       (1, 1, 2) ),
+      # 6. One define ended with an expand.
+      (u'a\nb\n//%PDDM-DEFINE bar()\n//%body2\n'
+       u'//%PDDM-EXPAND bar()\nbody2\n//%PDDM-EXPAND-END\n',
+       (2, 2, 1) ),
+      # 7. Two expands (one end), one define.
+      (u'a\n//%PDDM-EXPAND foo(1)\nbody\n//%PDDM-EXPAND foo(2)\nbody2\n//%PDDM-EXPAND-END\n'
+       u'//%PDDM-DEFINE foo()\n//%body2\n',
+       (1, 2, 2) ),
+    ]
+    for idx, (input_str, line_counts) in enumerate(test_list, 1):
+      f = io.StringIO(input_str)
+      sf = pddm.SourceFile(f)
+      sf._ParseFile()
+      self.assertEqual(len(sf._sections), len(line_counts),
+                       'Entry %d -- %d != %d' %
+                       (idx, len(sf._sections), len(line_counts)))
+      for idx2, (sec, expected) in enumerate(zip(sf._sections, line_counts), 1):
+        self.assertEqual(sec.num_lines_captured, expected,
+                         'Entry %d, section %d -- %d != %d' %
+                         (idx, idx2, sec.num_lines_captured, expected))
+
+  def testErrors(self):
+    test_list = [
+      # 1. Directive within expansion
+      (u'//%PDDM-EXPAND a()\n//%PDDM-BOGUS',
+       'Ran into directive ("//%PDDM-BOGUS", line 2) while in "//%PDDM-EXPAND a()".'),
+      (u'//%PDDM-EXPAND a()\n//%PDDM-DEFINE a()\n//%body\n',
+       'Ran into directive ("//%PDDM-DEFINE", line 2) while in "//%PDDM-EXPAND a()".'),
+      # 3. Expansion ran off end of file
+      (u'//%PDDM-EXPAND a()\na\nb\n',
+       'Hit the end of the file while in "//%PDDM-EXPAND a()".'),
+      # 4. Directive within define
+      (u'//%PDDM-DEFINE a()\n//%body\n//%PDDM-BOGUS',
+       'Ran into directive ("//%PDDM-BOGUS", line 3) while in "//%PDDM-DEFINE a()".'),
+      (u'//%PDDM-DEFINE a()\n//%body\n//%PDDM-EXPAND-END a()',
+       'Ran into directive ("//%PDDM-EXPAND-END", line 3) while in "//%PDDM-DEFINE a()".'),
+      # 6. Directives that shouldn't start sections
+      (u'a\n//%PDDM-DEFINE-END a()\n//a\n',
+       'Unexpected line 2: "//%PDDM-DEFINE-END a()".'),
+      (u'a\n//%PDDM-EXPAND-END a()\n//a\n',
+       'Unexpected line 2: "//%PDDM-EXPAND-END a()".'),
+      (u'//%PDDM-BOGUS\n//a\n',
+       'Unexpected line 1: "//%PDDM-BOGUS".'),
+    ]
+    for idx, (input_str, expected_err) in enumerate(test_list, 1):
+      f = io.StringIO(input_str)
+      try:
+        pddm.SourceFile(f)._ParseFile()
+        self.fail('Should throw exception, entry %d' % idx)
+      except pddm.PDDMError as e:
+        self.assertEqual(e.message, expected_err,
+                        'Entry %d failed: %r' % (idx, e))
+
+class TestProcessingSource(unittest.TestCase):
+
+  def testBasics(self):
+    input_str = u"""
+//%PDDM-IMPORT-DEFINES ImportFile
+foo
+//%PDDM-EXPAND mumble(abc)
+//%PDDM-EXPAND-END
+bar
+//%PDDM-EXPAND mumble(def)
+//%PDDM-EXPAND mumble(ghi)
+//%PDDM-EXPAND-END
+baz
+//%PDDM-DEFINE mumble(a_)
+//%a_: getName(a_)
+"""
+    input_str2 = u"""
+//%PDDM-DEFINE getName(x_)
+//%do##x_$u##(int x_);
+
+"""
+    expected = u"""
+//%PDDM-IMPORT-DEFINES ImportFile
+foo
+//%PDDM-EXPAND mumble(abc)
+// This block of code is generated, do not edit it directly.
+
+abc: doAbc(int abc);
+//%PDDM-EXPAND-END mumble(abc)
+bar
+//%PDDM-EXPAND mumble(def)
+// This block of code is generated, do not edit it directly.
+
+def: doDef(int def);
+//%PDDM-EXPAND mumble(ghi)
+// This block of code is generated, do not edit it directly.
+
+ghi: doGhi(int ghi);
+//%PDDM-EXPAND-END (2 expansions)
+baz
+//%PDDM-DEFINE mumble(a_)
+//%a_: getName(a_)
+"""
+    expected_stripped = u"""
+//%PDDM-IMPORT-DEFINES ImportFile
+foo
+//%PDDM-EXPAND mumble(abc)
+//%PDDM-EXPAND-END mumble(abc)
+bar
+//%PDDM-EXPAND mumble(def)
+//%PDDM-EXPAND mumble(ghi)
+//%PDDM-EXPAND-END (2 expansions)
+baz
+//%PDDM-DEFINE mumble(a_)
+//%a_: getName(a_)
+"""
+    def _Resolver(name):
+      self.assertEqual(name, 'ImportFile')
+      return io.StringIO(input_str2)
+    f = io.StringIO(input_str)
+    sf = pddm.SourceFile(f, _Resolver)
+    sf.ProcessContent()
+    self.assertEqual(sf.processed_content, expected)
+    # Feed it through and nothing should change.
+    f2 = io.StringIO(sf.processed_content)
+    sf2 = pddm.SourceFile(f2, _Resolver)
+    sf2.ProcessContent()
+    self.assertEqual(sf2.processed_content, expected)
+    self.assertEqual(sf2.processed_content, sf.processed_content)
+    # Test stripping (with the original input and expanded version).
+    f2 = io.StringIO(input_str)
+    sf2 = pddm.SourceFile(f2)
+    sf2.ProcessContent(strip_expansion=True)
+    self.assertEqual(sf2.processed_content, expected_stripped)
+    f2 = io.StringIO(sf.processed_content)
+    sf2 = pddm.SourceFile(f2, _Resolver)
+    sf2.ProcessContent(strip_expansion=True)
+    self.assertEqual(sf2.processed_content, expected_stripped)
+
+  def testProcessFileWithMacroParseError(self):
+    input_str = u"""
+foo
+//%PDDM-DEFINE mumble(a_)
+//%body
+//%PDDM-DEFINE mumble(x_)
+//%body2
+
+"""
+    f = io.StringIO(input_str)
+    sf = pddm.SourceFile(f)
+    try:
+      sf.ProcessContent()
+      self.fail('Should throw exception, entry %d' % idx)
+    except pddm.PDDMError as e:
+      self.assertEqual(e.message,
+                       'Attempt to redefine macro: "PDDM-DEFINE mumble(x_)"\n'
+                       '...while parsing section that started:\n'
+                       '  Line 3: //%PDDM-DEFINE mumble(a_)')
+
+  def testProcessFileWithExpandError(self):
+    input_str = u"""
+foo
+//%PDDM-DEFINE mumble(a_)
+//%body
+//%PDDM-EXPAND foobar(x_)
+//%PDDM-EXPAND-END
+
+"""
+    f = io.StringIO(input_str)
+    sf = pddm.SourceFile(f)
+    try:
+      sf.ProcessContent()
+      self.fail('Should throw exception, entry %d' % idx)
+    except pddm.PDDMError as e:
+      self.assertEqual(e.message,
+                       'No macro named "foobar".\n'
+                       '...while expanding "foobar(x_)" from the section that'
+                       ' started:\n   Line 5: //%PDDM-EXPAND foobar(x_)')
+
+
+if __name__ == '__main__':
+  unittest.main()