1 files changed, 12 insertions, 5 deletions
diff --git a/python/google/protobuf/internal/_parameterized.py b/python/google/protobuf/internal/_parameterized.py
index 400b2216..3821b916 100755
--- a/python/google/protobuf/internal/_parameterized.py
+++ b/python/google/protobuf/internal/_parameterized.py
@@ -149,9 +149,14 @@ import collections
 import functools
 import re
 import types
-import unittest
+try:
+  import unittest2 as unittest
+except ImportError:
+  import unittest
 import uuid
 
+import six
+
 ADDR_RE = re.compile(r'\<([a-zA-Z0-9_\-\.]+) object at 0x[a-fA-F0-9]+\>')
 _SEPARATOR = uuid.uuid1().hex
 _FIRST_ARG = object()
@@ -170,13 +175,13 @@ def _StrClass(cls):
 
 def _NonStringIterable(obj):
   return (isinstance(obj, collections.Iterable) and not
-          isinstance(obj, basestring))
+          isinstance(obj, six.string_types))
 
 
 def _FormatParameterList(testcase_params):
   if isinstance(testcase_params, collections.Mapping):
     return ', '.join('%s=%s' % (argname, _CleanRepr(value))
-                     for argname, value in testcase_params.iteritems())
+                     for argname, value in testcase_params.items())
   elif _NonStringIterable(testcase_params):
     return ', '.join(map(_CleanRepr, testcase_params))
   else:
@@ -258,7 +263,9 @@ def _ModifyClass(class_object, testcases, naming_type):
       'Cannot add parameters to %s,'
       ' which already has parameterized methods.' % (class_object,))
   class_object._id_suffix = id_suffix = {}
-  for name, obj in class_object.__dict__.items():
+  # We change the size of __dict__ while we iterate over it, 
+  # which Python 3.x will complain about, so use copy().
+  for name, obj in class_object.__dict__.copy().items():
     if (name.startswith(unittest.TestLoader.testMethodPrefix)
         and isinstance(obj, types.FunctionType)):
       delattr(class_object, name)
@@ -266,7 +273,7 @@ def _ModifyClass(class_object, testcases, naming_type):
       _UpdateClassDictForParamTestCase(
           methods, id_suffix, name,
           _ParameterizedTestIter(obj, testcases, naming_type))
-      for name, meth in methods.iteritems():
+      for name, meth in methods.items():
         setattr(class_object, name, meth)