1 files changed, 75 insertions, 0 deletions
diff --git a/Lib/unittest/util.py b/Lib/unittest/util.py
new file mode 100644
index 0000000000..26805def31
--- /dev/null
+++ b/Lib/unittest/util.py
@@ -0,0 +1,75 @@
+"""Various utility functions."""
+
+def strclass(cls):
+    return "%s.%s" % (cls.__module__, cls.__name__)
+
+def sorted_list_difference(expected, actual):
+    """Finds elements in only one or the other of two, sorted input lists.
+
+    Returns a two-element tuple of lists.    The first list contains those
+    elements in the "expected" list but not in the "actual" list, and the
+    second contains those elements in the "actual" list but not in the
+    "expected" list.    Duplicate elements in either input list are ignored.
+    """
+    i = j = 0
+    missing = []
+    unexpected = []
+    while True:
+        try:
+            e = expected[i]
+            a = actual[j]
+            if e < a:
+                missing.append(e)
+                i += 1
+                while expected[i] == e:
+                    i += 1
+            elif e > a:
+                unexpected.append(a)
+                j += 1
+                while actual[j] == a:
+                    j += 1
+            else:
+                i += 1
+                try:
+                    while expected[i] == e:
+                        i += 1
+                finally:
+                    j += 1
+                    while actual[j] == a:
+                        j += 1
+        except IndexError:
+            missing.extend(expected[i:])
+            unexpected.extend(actual[j:])
+            break
+    return missing, unexpected
+
+
+def unorderable_list_difference(expected, actual):
+    """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 = []
+    while expected:
+        item = expected.pop()
+        try:
+            actual.remove(item)
+        except ValueError:
+            missing.append(item)
+
+    # anything left in actual is unexpected
+    return missing, actual
+
+def CmpToKey(mycmp):
+    'Convert a cmp= function into a key= function'
+    class K(object):
+        def __init__(self, obj, *args):
+            self.obj = obj
+        def __lt__(self, other):
+            return mycmp(self.obj, other.obj) == -1
+    return K
+
+def three_way_cmp(x, y):
+    """Return -1 if x < y, 0 if x == y and 1 if x > y"""
+    return (x > y) - (x < y)