Fixed bug 1726, with a test case.

Refactored tests for easier readability.

lib/python/ZopeUndo/Prefix.py

@@ -20,20 +20,28 @@
 """
 
 class Prefix:
-    """A Prefix() is equal to any string it as a prefix of.
+    """A Prefix() is equal to any path it is a prefix of.
 
-    This class can be compared to a string (or arbitrary sequence).
-    The comparison will return True if the prefix value is a prefix of
-    the string being compared.
 
-    Two prefixes can not be compared.
+    This class can be compared to a string.
+    The comparison will return True if all path elements of the
+    Prefix are found at the beginning of the string being compared.
+
+    Two Prefixes can not be compared.
     """
 
     __no_side_effects__ = 1
 
     def __init__(self, path):
-        self.value = len(path), path
+        path_list = path.split('/')
+        self.length = len(path_list)
+        self.path = path_list
 
     def __cmp__(self, o):
-        l, v = self.value
-        return cmp(o[:l], v)
+        other_path = o.split('/')
+        return cmp(other_path[:self.length], self.path)
+
+    def __repr__(self):
+        # makes failing tests easier to read
+        return "Prefix('%s')" % '/'.join(self.path)
+

lib/python/ZopeUndo/tests/testPrefix.py

@@ -18,19 +18,15 @@
 class PrefixTest(unittest.TestCase):
 
     def test(self):
-        p1 = (Prefix("/a/b"),
-              ("/a/b", "/a/b/c", "/a/b/c/d"),
-              ("", "/a/c"))
-
-        p2 = (Prefix(""),
-              ("", "/def", "/a/b", "/a/b/c", "/a/b/c/d"),
-              ())
-
-        for prefix, equal, notequal in p1, p2:
-            for s in equal:
-                self.assertEqual(prefix, s)
-            for s in notequal:
-                self.assertNotEqual(prefix, s)
+        p1 = Prefix("/a/b")
+        for equal in ("/a/b", "/a/b/c", "/a/b/c/d"):
+            self.assertEqual(p1, equal)
+        for notEqual in ("", "/a/c", "/a/bbb", "///"):
+            self.assertNotEqual(p1, notEqual)
 
+        p2 = Prefix("")
+        for equal in ("", "/", "/def", "/a/b", "/a/b/c", "/a/b/c/d"):
+            self.assertEqual(p2, equal)
+
 def test_suite():
     return unittest.makeSuite(PrefixTest)