From 9fd12d8a8ad99d386dcd64fe7f4aca084345d39b Mon Sep 17 00:00:00 2001
From: Srinivas Reddy Thatiparthy <thatiparthysreenivas@gmail.com>
Date: Mon, 22 Oct 2018 08:40:51 +0530
Subject: [PATCH] Fixed bpo-19217: Calling assertEquals for moderately long
 list takes too long

---
 Lib/unittest/case.py                 | 7 ++++---
 Lib/unittest/test/test_assertions.py | 4 ++--
 Lib/unittest/test/test_case.py       | 6 ++++--
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index 2579c30474b5366..f3c65931528f41e 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -1013,9 +1013,10 @@ def assertSequenceEqual(self, seq1, seq2, msg=None, seq_type=None):
                     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()))
+        diffMsg = difflib.unified_diff(pprint.pformat(seq1).splitlines(),
+                                       pprint.pformat(seq2).splitlines(),
+                                       lineterm='')
+        diffMsg = '\n' + '\n'.join(diffMsg)
 
         standardMsg = self._truncateMessage(standardMsg, diffMsg)
         msg = self._formatMessage(msg, standardMsg)
diff --git a/Lib/unittest/test/test_assertions.py b/Lib/unittest/test/test_assertions.py
index f5e64d68e7b1014..14a8f231e1c023b 100644
--- a/Lib/unittest/test/test_assertions.py
+++ b/Lib/unittest/test/test_assertions.py
@@ -242,8 +242,8 @@ def testAssertSequenceEqual(self):
         # Error messages are multiline so not testing on full message
         # assertTupleEqual and assertListEqual delegate to this method
         self.assertMessages('assertSequenceEqual', ([], [None]),
-                            [r"\+ \[None\]$", "^oops$", r"\+ \[None\]$",
-                             r"\+ \[None\] : oops$"])
+                            [r"\+\[None\]$", "^oops$", r"\+\[None\]$",
+                             r"\+\[None\] : oops$"])
 
     def testAssertSetEqual(self):
         self.assertMessages('assertSetEqual', (set(), set([None])),
diff --git a/Lib/unittest/test/test_case.py b/Lib/unittest/test/test_case.py
index 687fe5b65f109e7..68fbdef7665b9c0 100644
--- a/Lib/unittest/test/test_case.py
+++ b/Lib/unittest/test/test_case.py
@@ -789,8 +789,10 @@ def testAssertSequenceEqualMaxDiff(self):
         self.assertEqual(self.maxDiff, 80*8)
         seq1 = 'a' + 'x' * 80**2
         seq2 = 'b' + 'x' * 80**2
-        diff = '\n'.join(difflib.ndiff(pprint.pformat(seq1).splitlines(),
-                                       pprint.pformat(seq2).splitlines()))
+        diff = difflib.unified_diff(pprint.pformat(seq1).splitlines(),
+                                    pprint.pformat(seq2).splitlines(),
+                                    lineterm='')
+        diff = '\n'.join(diff)
         # the +1 is the leading \n added by assertSequenceEqual
         omitted = unittest.case.DIFF_OMITTED % (len(diff) + 1,)