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Viewing changes to Lib/test/test_hash.py

  • Committer: Jeffrey C. "The TimeHorse" Jacobs
  • Date: 2008-09-21 13:47:31 UTC
  • mfrom: (39021.1.404 Regexp-2.7)
  • mto: This revision was merged to the branch mainline in revision 39030.
  • Revision ID: darklord@timehorse.com-20080921134731-rudomuzeh1b2tz1y
Merged in changes from the latest python source snapshot.

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Lib/test/test_hash.py
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# test the invariant that
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#   iff a==b then hash(a)==hash(b)
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#
 
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# Also test that hash implementations are inherited as expected
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import unittest
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from test import test_support
 
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from collections import Hashable
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class HashEqualityTestCase(unittest.TestCase):
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        self.same_hash(float(0.5), complex(0.5, 0.0))
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_default_hash = object.__hash__
 
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class DefaultHash(object): pass
 
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_FIXED_HASH_VALUE = 42
 
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class FixedHash(object):
 
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    def __hash__(self):
 
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        return _FIXED_HASH_VALUE
 
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class OnlyEquality(object):
 
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    def __eq__(self, other):
 
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        return self is other
 
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    # Trick to suppress Py3k warning in 2.x
 
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    __hash__ = None
 
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del OnlyEquality.__hash__
 
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class OnlyInequality(object):
 
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    def __ne__(self, other):
 
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        return self is not other
 
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class OnlyCmp(object):
 
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    def __cmp__(self, other):
 
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        return cmp(id(self), id(other))
 
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    # Trick to suppress Py3k warning in 2.x
 
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    __hash__ = None
 
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del OnlyCmp.__hash__
 
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class InheritedHashWithEquality(FixedHash, OnlyEquality): pass
 
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class InheritedHashWithInequality(FixedHash, OnlyInequality): pass
 
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class InheritedHashWithCmp(FixedHash, OnlyCmp): pass
 
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class NoHash(object):
 
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    __hash__ = None
 
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class HashInheritanceTestCase(unittest.TestCase):
 
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    default_expected = [object(),
 
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                        DefaultHash(),
 
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                        OnlyEquality(),
 
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                        OnlyInequality(),
 
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                        OnlyCmp(),
 
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                       ]
 
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    fixed_expected = [FixedHash(),
 
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                      InheritedHashWithEquality(),
 
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                      InheritedHashWithInequality(),
 
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                      InheritedHashWithCmp(),
 
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                      ]
 
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    error_expected = [NoHash()]
 
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    def test_default_hash(self):
 
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        for obj in self.default_expected:
 
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            self.assertEqual(hash(obj), _default_hash(obj))
 
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    def test_fixed_hash(self):
 
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        for obj in self.fixed_expected:
 
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            self.assertEqual(hash(obj), _FIXED_HASH_VALUE)
 
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    def test_error_hash(self):
 
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        for obj in self.error_expected:
 
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            self.assertRaises(TypeError, hash, obj)
 
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    def test_hashable(self):
 
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        objects = (self.default_expected +
 
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                   self.fixed_expected)
 
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        for obj in objects:
 
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            self.assert_(isinstance(obj, Hashable), repr(obj))
 
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    def test_not_hashable(self):
 
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        for obj in self.error_expected:
 
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            self.assertFalse(isinstance(obj, Hashable), repr(obj))
 
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def test_main():
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    test_support.run_unittest(HashEqualityTestCase)
 
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    test_support.run_unittest(HashEqualityTestCase,
 
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                              HashInheritanceTestCase)
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if __name__ == "__main__":