test_weakref.py

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        #
        dict, objects = self.make_weak_valued_dict()
        for o in objects:
            self.assert_(weakref.getweakrefcount(o) == 1,
                         "wrong number of weak references to %r!" % o)
            self.assert_(o is dict[o.arg],
                         "wrong object returned by weak dict!")
        items1 = dict.items()
        items2 = dict.copy().items()
        items1.sort()
        items2.sort()
        self.assert_(items1 == items2,
                     "cloning of weak-valued dictionary did not work!")
        del items1, items2
        self.assert_(len(dict) == self.COUNT)
        del objects[0]
        self.assert_(len(dict) == (self.COUNT - 1),
                     "deleting object did not cause dictionary update")
        del objects, o
        self.assert_(len(dict) == 0,
                     "deleting the values did not clear the dictionary")
        # regression on SF bug #447152:
        dict = weakref.WeakValueDictionary()
        self.assertRaises(KeyError, dict.__getitem__, 1)
        dict[2] = C()
        self.assertRaises(KeyError, dict.__getitem__, 2)

    def test_weak_keys(self):
        #
        #  This exercises d.copy(), d.items(), d[] = v, d[], del d[],
        #  len(d), d.has_key().
        #
        dict, objects = self.make_weak_keyed_dict()
        for o in objects:
            self.assert_(weakref.getweakrefcount(o) == 1,
                         "wrong number of weak references to %r!" % o)
            self.assert_(o.arg is dict[o],
                         "wrong object returned by weak dict!")
        items1 = dict.items()
        items2 = dict.copy().items()
        items1.sort()
        items2.sort()
        self.assert_(items1 == items2,
                     "cloning of weak-keyed dictionary did not work!")
        del items1, items2
        self.assert_(len(dict) == self.COUNT)
        del objects[0]
        self.assert_(len(dict) == (self.COUNT - 1),
                     "deleting object did not cause dictionary update")
        del objects, o
        self.assert_(len(dict) == 0,
                     "deleting the keys did not clear the dictionary")
        o = Object(42)
        dict[o] = "What is the meaning of the universe?"
        self.assert_(dict.has_key(o))
        self.assert_(not dict.has_key(34))

    def test_weak_keyed_iters(self):
        dict, objects = self.make_weak_keyed_dict()
        self.check_iters(dict)

    def test_weak_valued_iters(self):
        dict, objects = self.make_weak_valued_dict()
        self.check_iters(dict)

    def check_iters(self, dict):
        # item iterator:
        items = dict.items()
        for item in dict.iteritems():
            items.remove(item)
        self.assert_(len(items) == 0, "iteritems() did not touch all items")

        # key iterator, via __iter__():
        keys = dict.keys()
        for k in dict:
            keys.remove(k)
        self.assert_(len(keys) == 0, "__iter__() did not touch all keys")

        # key iterator, via iterkeys():
        keys = dict.keys()
        for k in dict.iterkeys():
            keys.remove(k)
        self.assert_(len(keys) == 0, "iterkeys() did not touch all keys")

        # value iterator:
        values = dict.values()
        for v in dict.itervalues():
            values.remove(v)
        self.assert_(len(values) == 0, "itervalues() did not touch all values")

    def test_make_weak_keyed_dict_from_dict(self):
        o = Object(3)
        dict = weakref.WeakKeyDictionary({o:364})
        self.assert_(dict[o] == 364)

    def test_make_weak_keyed_dict_from_weak_keyed_dict(self):
        o = Object(3)
        dict = weakref.WeakKeyDictionary({o:364})
        dict2 = weakref.WeakKeyDictionary(dict)
        self.assert_(dict[o] == 364)

    def make_weak_keyed_dict(self):
        dict = weakref.WeakKeyDictionary()
        objects = map(Object, range(self.COUNT))
        for o in objects:
            dict[o] = o.arg
        return dict, objects

    def make_weak_valued_dict(self):
        dict = weakref.WeakValueDictionary()
        objects = map(Object, range(self.COUNT))
        for o in objects:
            dict[o.arg] = o
        return dict, objects

    def check_popitem(self, klass, key1, value1, key2, value2):
        weakdict = klass()
        weakdict[key1] = value1
        weakdict[key2] = value2
        self.assert_(len(weakdict) == 2)
        k, v = weakdict.popitem()
        self.assert_(len(weakdict) == 1)
        if k is key1:
            self.assert_(v is value1)
        else:
            self.assert_(v is value2)
        k, v = weakdict.popitem()
        self.assert_(len(weakdict) == 0)
        if k is key1:
            self.assert_(v is value1)
        else:
            self.assert_(v is value2)

    def test_weak_valued_dict_popitem(self):
        self.check_popitem(weakref.WeakValueDictionary,
                           "key1", C(), "key2", C())

    def test_weak_keyed_dict_popitem(self):
        self.check_popitem(weakref.WeakKeyDictionary,
                           C(), "value 1", C(), "value 2")

    def check_setdefault(self, klass, key, value1, value2):
        self.assert_(value1 is not value2,
                     "invalid test"
                     " -- value parameters must be distinct objects")
        weakdict = klass()
        o = weakdict.setdefault(key, value1)
        self.assert_(o is value1)
        self.assert_(weakdict.has_key(key))
        self.assert_(weakdict.get(key) is value1)
        self.assert_(weakdict[key] is value1)

        o = weakdict.setdefault(key, value2)
        self.assert_(o is value1)
        self.assert_(weakdict.has_key(key))
        self.assert_(weakdict.get(key) is value1)
        self.assert_(weakdict[key] is value1)

    def test_weak_valued_dict_setdefault(self):
        self.check_setdefault(weakref.WeakValueDictionary,
                              "key", C(), C())

    def test_weak_keyed_dict_setdefault(self):
        self.check_setdefault(weakref.WeakKeyDictionary,
                              C(), "value 1", "value 2")

    def check_update(self, klass, dict):
        #
        #  This exercises d.update(), len(d), d.keys(), d.has_key(),
        #  d.get(), d[].
        #
        weakdict = klass()
        weakdict.update(dict)
        self.assert_(len(weakdict) == len(dict))
        for k in weakdict.keys():
            self.assert_(dict.has_key(k),
                         "mysterious new key appeared in weak dict")
            v = dict.get(k)
            self.assert_(v is weakdict[k])
            self.assert_(v is weakdict.get(k))
        for k in dict.keys():
            self.assert_(weakdict.has_key(k),
                         "original key disappeared in weak dict")
            v = dict[k]
            self.assert_(v is weakdict[k])
            self.assert_(v is weakdict.get(k))

    def test_weak_valued_dict_update(self):
        self.check_update(weakref.WeakValueDictionary,
                          {1: C(), 'a': C(), C(): C()})

    def test_weak_keyed_dict_update(self):
        self.check_update(weakref.WeakKeyDictionary,
                          {C(): 1, C(): 2, C(): 3})

    def test_weak_keyed_delitem(self):
        d = weakref.WeakKeyDictionary()
        o1 = Object('1')
        o2 = Object('2')
        d[o1] = 'something'
        d[o2] = 'something'
        self.assert_(len(d) == 2)
        del d[o1]
        self.assert_(len(d) == 1)
        self.assert_(d.keys() == [o2])

    def test_weak_valued_delitem(self):
        d = weakref.WeakValueDictionary()
        o1 = Object('1')
        o2 = Object('2')
        d['something'] = o1
        d['something else'] = o2
        self.assert_(len(d) == 2)
        del d['something']
        self.assert_(len(d) == 1)
        self.assert_(d.items() == [('something else', o2)])

    def test_weak_keyed_bad_delitem(self):
        d = weakref.WeakKeyDictionary()
        o = Object('1')
        # An attempt to delete an object that isn't there should raise
        # KeyError.  It didn't before 2.3.
        self.assertRaises(KeyError, d.__delitem__, o)
        self.assertRaises(KeyError, d.__getitem__, o)

        # If a key isn't of a weakly referencable type, __getitem__ and
        # __setitem__ raise TypeError.  __delitem__ should too.
        self.assertRaises(TypeError, d.__delitem__,  13)
        self.assertRaises(TypeError, d.__getitem__,  13)
        self.assertRaises(TypeError, d.__setitem__,  13, 13)

    def test_weak_keyed_cascading_deletes(self):
        # SF bug 742860.  For some reason, before 2.3 __delitem__ iterated
        # over the keys via self.data.iterkeys().  If things vanished from
        # the dict during this (or got added), that caused a RuntimeError.

        d = weakref.WeakKeyDictionary()
        mutate = False

        class C(object):
            def __init__(self, i):
                self.value = i
            def __hash__(self):
                return hash(self.value)
            def __eq__(self, other):
                if mutate:
                    # Side effect that mutates the dict, by removing the
                    # last strong reference to a key.
                    del objs[-1]
                return self.value == other.value

        objs = [C(i) for i in range(4)]
        for o in objs:
            d[o] = o.value
        del o   # now the only strong references to keys are in objs
        # Find the order in which iterkeys sees the keys.
        objs = d.keys()
        # Reverse it, so that the iteration implementation of __delitem__
        # has to keep looping to find the first object we delete.
        objs.reverse()

        # Turn on mutation in C.__eq__.  The first time thru the loop,
        # under the iterkeys() business the first comparison will delete
        # the last item iterkeys() would see, and that causes a
        #     RuntimeError: dictionary changed size during iteration
        # when the iterkeys() loop goes around to try comparing the next
        # key.  After this was fixed, it just deletes the last object *our*
        # "for o in obj" loop would have gotten to.
        mutate = True
        count = 0
        for o in objs:
            count += 1
            del d[o]
        self.assertEqual(len(d), 0)
        self.assertEqual(count, 2)

def test_main():
    loader = unittest.TestLoader()
    suite = unittest.TestSuite()
    suite.addTest(loader.loadTestsFromTestCase(ReferencesTestCase))
    suite.addTest(loader.loadTestsFromTestCase(MappingTestCase))
    test_support.run_suite(suite)


if __name__ == "__main__":
    test_main()