Issue 2235: __hash__ is once again inherited by default, but inheritance can be blocked explicitly so that collections.Hashable remains meaningful

Lib/test/test_richcmp.py

@@ -48,8 +48,7 @@ class Vector:
     def __setitem__(self, i, v):
         self.data[i] = v
 
-    def __hash__(self):
-        raise TypeError, "Vectors cannot be hashed"
+    __hash__ = None # Vectors cannot be hashed
 
     def __nonzero__(self):
         raise TypeError, "Vectors cannot be used in Boolean contexts"
@@ -85,35 +84,6 @@ class Vector:
             raise ValueError, "Cannot compare vectors of different length"
         return other
 
-
-class SimpleOrder(object):
-    """
-    A simple class that defines order but not full comparison.
-    """
-
-    def __init__(self, value):
-        self.value = value
-
-    def __lt__(self, other):
-        if not isinstance(other, SimpleOrder):
-            return True
-        return self.value < other.value
-
-    def __gt__(self, other):
-        if not isinstance(other, SimpleOrder):
-            return False
-        return self.value > other.value
-
-
-class DumbEqualityWithoutHash(object):
-    """
-    A class that define __eq__, but no __hash__: it shouldn't be hashable.
-    """
-
-    def __eq__(self, other):
-        return False
-
-
 opmap = {
     "lt": (lambda a,b: a< b, operator.lt, operator.__lt__),
     "le": (lambda a,b: a<=b, operator.le, operator.__le__),
@@ -359,39 +329,8 @@ class ListTest(unittest.TestCase):
         for op in opmap["lt"]:
             self.assertIs(op(x, y), True)
 
-
-class HashableTest(unittest.TestCase):
-    """
-    Test hashability of classes with rich operators defined.
-    """
-
-    def test_simpleOrderHashable(self):
-        """
-        A class that only defines __gt__ and/or __lt__ should be hashable.
-        """
-        a = SimpleOrder(1)
-        b = SimpleOrder(2)
-        self.assert_(a < b)
-        self.assert_(b > a)
-        self.assert_(a.__hash__ is not None)
-
-    def test_notHashableException(self):
-        """
-        If a class is not hashable, it should raise a TypeError with an
-        understandable message.
-        """
-        a = DumbEqualityWithoutHash()
-        try:
-            hash(a)
-        except TypeError, e:
-            self.assertEquals(str(e),
-                              "unhashable type: 'DumbEqualityWithoutHash'")
-        else:
-            raise test_support.TestFailed("Should not be here")
-
-
 def test_main():
-    test_support.run_unittest(VectorTest, NumberTest, MiscTest, DictTest, ListTest, HashableTest)
+    test_support.run_unittest(VectorTest, NumberTest, MiscTest, DictTest, ListTest)
 
 if __name__ == "__main__":
     test_main()