Patch for Py3k with fallback for comparing unsortable sequences in

assertSameElements.

Removed the expected failure and added another test case to confirm that
this patch works for unsortable sequences that are the same (no fail)
and different (fail).

Issue #2578

2 files changed, 25 insertions, 5 deletions

diff --git a/Lib/test/test_unittest.py b/Lib/test/test_unittest.py
index 33204f87b1..aaa3dc545f 100644
--- a/Lib/test/test_unittest.py
+++ b/Lib/test/test_unittest.py
@@ -2392,8 +2392,6 @@ class Test_TestCase(TestCase, TestEquality, TestHashing):
             self.assertRaises(self.failureException, self.assertEqual, a, b,
                               msg='foo')
 
-    # The fact that dictionaries are unorderable breaks this test for them.
-    @unittest.expectedFailure
     def testEquality(self):
         self.assertListEqual([], [])
         self.assertTupleEqual((), ())
@@ -2459,6 +2457,8 @@ class Test_TestCase(TestCase, TestEquality, TestHashing):
         self.assertSameElements([{'a': 1}, {'b': 2}], [{'b': 2}, {'a': 1}])
         self.assertRaises(self.failureException, self.assertSameElements,
                           [[1]], [[2]])
+        self.assertRaises(self.failureException, self.assertSameElements,
+                          [{'a': 1}, {'b': 2}], [{'b': 2}, {'a': 2}])
 
     def testAssertSetEqual(self):
         set1 = set()
diff --git a/Lib/unittest.py b/Lib/unittest.py
index 16a866343f..244a45beec 100644
--- a/Lib/unittest.py
+++ b/Lib/unittest.py
@@ -858,9 +858,13 @@ class TestCase(object):
             # not hashable.
             expected = list(expected_seq)
             actual = list(actual_seq)
-            expected.sort()
-            actual.sort()
-            missing, unexpected = _SortedListDifference(expected, actual)
+            try:
+                expected.sort()
+                actual.sort()
+            except TypeError:
+                missing, unexpected = _UnorderableListDifference(expected, actual)
+            else:
+                missing, unexpected = _SortedListDifference(expected, actual)
         errors = []
         if missing:
             errors.append('Expected, but missing:\n    %r' % missing)
@@ -985,6 +989,22 @@ def _SortedListDifference(expected, actual):
             break
     return missing, unexpected
 
+def _UnorderableListDifference(expected, actual):
+    """Same behavior as _SortedListDifference but
+    for lists of unorderable items (like dicts).
+
+    As it does a linear search per item (remove) it
+    has O(n*n) performance."""
+    missing = []
+    while expected:
+        item = expected.pop()
+        try:
+            actual.remove(item)
+        except ValueError:
+            missing.append(item)
+
+    # anything left in actual is unexpected
+    return missing, actual
 
 class TestSuite(object):
     """A test suite is a composite test consisting of a number of TestCases.