1 files changed, 37 insertions, 0 deletions
diff --git a/Lib/unittest/util.py b/Lib/unittest/util.py
index 9fce625..9ddf879 100644
--- a/Lib/unittest/util.py
+++ b/Lib/unittest/util.py
@@ -48,3 +48,40 @@ def sorted_list_difference(expected, actual):
             unexpected.extend(actual[j:])
             break
     return missing, unexpected
+
+
+def unorderable_list_difference(expected, actual, ignore_duplicate=False):
+    """Same behavior as sorted_list_difference but
+    for lists of unorderable items (like dicts).
+
+    As it does a linear search per item (remove) it
+    has O(n*n) performance.
+    """
+    missing = []
+    unexpected = []
+    while expected:
+        item = expected.pop()
+        try:
+            actual.remove(item)
+        except ValueError:
+            missing.append(item)
+        if ignore_duplicate:
+            for lst in expected, actual:
+                try:
+                    while True:
+                        lst.remove(item)
+                except ValueError:
+                    pass
+    if ignore_duplicate:
+        while actual:
+            item = actual.pop()
+            unexpected.append(item)
+            try:
+                while True:
+                    actual.remove(item)
+            except ValueError:
+                pass
+        return missing, unexpected
+
+    # anything left in actual is unexpected
+    return missing, actual