split unittest.py into a package

Lib/unittest/util.py

@@ -0,0 +1,44 @@
+"""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