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

1 files changed, 23 insertions, 3 deletions

diff --git a/Lib/unittest.py b/Lib/unittest.py
index 16a8663..244a45b 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.