test_dict.py 文件源码

def test_fromkeys(self):
        self.assertEqual(dict.fromkeys('abc'), {'a':None, 'b':None, 'c':None})
        d = {}
        self.assertIsNot(d.fromkeys('abc'), d)
        self.assertEqual(d.fromkeys('abc'), {'a':None, 'b':None, 'c':None})
        self.assertEqual(d.fromkeys((4,5),0), {4:0, 5:0})
        self.assertEqual(d.fromkeys([]), {})
        def g():
            yield 1
        self.assertEqual(d.fromkeys(g()), {1:None})
        self.assertRaises(TypeError, {}.fromkeys, 3)
        class dictlike(dict): pass
        self.assertEqual(dictlike.fromkeys('a'), {'a':None})
        self.assertEqual(dictlike().fromkeys('a'), {'a':None})
        self.assertIsInstance(dictlike.fromkeys('a'), dictlike)
        self.assertIsInstance(dictlike().fromkeys('a'), dictlike)
        class mydict(dict):
            def __new__(cls):
                return collections.UserDict()
        ud = mydict.fromkeys('ab')
        self.assertEqual(ud, {'a':None, 'b':None})
        self.assertIsInstance(ud, collections.UserDict)
        self.assertRaises(TypeError, dict.fromkeys)

        class Exc(Exception): pass

        class baddict1(dict):
            def __init__(self):
                raise Exc()

        self.assertRaises(Exc, baddict1.fromkeys, [1])

        class BadSeq(object):
            def __iter__(self):
                return self
            def __next__(self):
                raise Exc()

        self.assertRaises(Exc, dict.fromkeys, BadSeq())

        class baddict2(dict):
            def __setitem__(self, key, value):
                raise Exc()

        self.assertRaises(Exc, baddict2.fromkeys, [1])

        # test fast path for dictionary inputs
        d = dict(zip(range(6), range(6)))
        self.assertEqual(dict.fromkeys(d, 0), dict(zip(range(6), [0]*6)))