bpo-37685: Fixed __eq__, __lt__ etc implementations in some classes. (GH-14952)

They now return NotImplemented for unsupported type of the other operand.

tests/test_version.py

@@ -45,6 +45,14 @@ class VersionTestCase(unittest.TestCase):
             self.assertEqual(res, wanted,
                              'cmp(%s, %s) should be %s, got %s' %
                              (v1, v2, wanted, res))
+            res = StrictVersion(v1)._cmp(v2)
+            self.assertEqual(res, wanted,
+                             'cmp(%s, %s) should be %s, got %s' %
+                             (v1, v2, wanted, res))
+            res = StrictVersion(v1)._cmp(object())
+            self.assertIs(res, NotImplemented,
+                          'cmp(%s, %s) should be NotImplemented, got %s' %
+                          (v1, v2, res))
 
 
     def test_cmp(self):
@@ -63,6 +71,14 @@ class VersionTestCase(unittest.TestCase):
             self.assertEqual(res, wanted,
                              'cmp(%s, %s) should be %s, got %s' %
                              (v1, v2, wanted, res))
+            res = LooseVersion(v1)._cmp(v2)
+            self.assertEqual(res, wanted,
+                             'cmp(%s, %s) should be %s, got %s' %
+                             (v1, v2, wanted, res))
+            res = LooseVersion(v1)._cmp(object())
+            self.assertIs(res, NotImplemented,
+                          'cmp(%s, %s) should be NotImplemented, got %s' %
+                          (v1, v2, res))
 
 def test_suite():
     return unittest.makeSuite(VersionTestCase)

version.py

@@ -166,6 +166,8 @@ class StrictVersion (Version):
     def _cmp (self, other):
         if isinstance(other, str):
             other = StrictVersion(other)
+        elif not isinstance(other, StrictVersion):
+            return NotImplemented
 
         if self.version != other.version:
             # numeric versions don't match
@@ -331,6 +333,8 @@ class LooseVersion (Version):
     def _cmp (self, other):
         if isinstance(other, str):
             other = LooseVersion(other)
+        elif not isinstance(other, LooseVersion):
+            return NotImplemented
 
         if self.version == other.version:
             return 0