diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -4,17 +4,17 @@ import sys
 import functools
 import difflib
 import pprint
 import re
 import warnings
 import collections
 
 from . import result
-from .util import (strclass, safe_repr, sorted_list_difference,
+from .util import (strclass, safe_repr, truncate_str, sorted_list_difference,
                    unorderable_list_difference, _count_diff_all_purpose,
                    _count_diff_hashable)
 
 __unittest = True
 
 
 DIFF_OMITTED = ('\nDiff is %s characters long. '
                  'Set self.maxDiff to None to see it.')
@@ -645,17 +645,26 @@ class TestCase(object):
             if asserter is not None:
                 return asserter
 
         return self._baseAssertEqual
 
     def _baseAssertEqual(self, first, second, msg=None):
         """The default assertEqual implementation, not type specific."""
         if not first == second:
-            standardMsg = '%s != %s' % (safe_repr(first), safe_repr(second))
+
+            firststring, secondstring = safe_repr(first), safe_repr(second)
+
+            # check that standardMsg will be shorter than maxDiff
+            if (self.maxDiff is not None and 
+                (len(firststring) + len(secondstring) + 8) > self.maxDiff):
+                standardMsg = '%s != %s' % (truncate_str(firststring, self.maxDiff),
+                                            truncate_str(secondstring, self.maxDiff))
+            else:
+                standardMsg = '%s != %s' % (firststring, secondstring)            
             msg = self._formatMessage(msg, standardMsg)
             raise self.failureException(msg)
 
     def assertEqual(self, first, second, msg=None):
         """Fail if the two objects are unequal as determined by the '=='
            operator.
         """
         assertion_func = self._getAssertEqualityFunc(first, second)
diff --git a/Lib/unittest/util.py b/Lib/unittest/util.py
--- a/Lib/unittest/util.py
+++ b/Lib/unittest/util.py
@@ -1,23 +1,27 @@
 """Various utility functions."""
 
 from collections import namedtuple, OrderedDict
 
 __unittest = True
 
 _MAX_LENGTH = 80
-def safe_repr(obj, short=False):
+def safe_repr(obj, short=False, maxLength = _MAX_LENGTH):
     try:
         result = repr(obj)
     except Exception:
         result = object.__repr__(obj)
-    if not short or len(result) < _MAX_LENGTH:
+    if not short or len(result) < maxLength:
         return result
-    return result[:_MAX_LENGTH] + ' [truncated]...'
+    return truncate_str(result, maxLength)
+
+def truncate_str (obj, maxLength = _MAX_LENGTH):
+    #Truncate a string and add a message 
+    return obj[:maxLength] + ' [truncated]...'
 
 def strclass(cls):
     return "%s.%s" % (cls.__module__, cls.__name__)
 
 def sorted_list_difference(expected, actual):
     """Finds elements in only one or the other of two, sorted input lists.
 
     Returns a two-element tuple of lists.    The first list contains those