diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -987,18 +987,20 @@ class TestCase(object):
                 try:
                     differing += ('First extra element %d:\n%s\n' %
                                   (len1, seq2[len1]))
                 except (TypeError, IndexError, NotImplementedError):
                     differing += ('Unable to index element %d '
                                   'of second %s\n' % (len1, seq_type_name))
         standardMsg = differing
         diffMsg = '\n' + '\n'.join(
-            difflib.ndiff(pprint.pformat(seq1).splitlines(),
-                          pprint.pformat(seq2).splitlines()))
+            difflib.unified_diff(pprint.pformat(seq1).splitlines(),
+                                 pprint.pformat(seq2).splitlines(),
+                                 lineterm='',
+                                ))
 
         standardMsg = self._truncateMessage(standardMsg, diffMsg)
         msg = self._formatMessage(msg, standardMsg)
         self.fail(msg)
 
     def _truncateMessage(self, message, diff):
         max_diff = self.maxDiff
         if max_diff is None or len(diff) <= max_diff: