Method test_basics

Lib/test/test_collections.py:90–148

(self)

class TestChainMap(unittest.TestCase):

    def test_basics(self):
        c = ChainMap()
        c['a'] = 1
        c['b'] = 2
        d = c.new_child()
        d['b'] = 20
        d['c'] = 30
        self.assertEqual(d.maps, [{'b':20, 'c':30}, {'a':1, 'b':2}])  # check internal state
        self.assertEqual(d.items(), dict(a=1, b=20, c=30).items())    # check items/iter/getitem
        self.assertEqual(len(d), 3)                                   # check len
        for key in 'abc':                                             # check contains
            self.assertIn(key, d)
        for k, v in dict(a=1, b=20, c=30, z=100).items():             # check get
            self.assertEqual(d.get(k, 100), v)

        del d['b']                                                    # unmask a value
        self.assertEqual(d.maps, [{'c':30}, {'a':1, 'b':2}])          # check internal state
        self.assertEqual(d.items(), dict(a=1, b=2, c=30).items())     # check items/iter/getitem
        self.assertEqual(len(d), 3)                                   # check len
        for key in 'abc':                                             # check contains
            self.assertIn(key, d)
        for k, v in dict(a=1, b=2, c=30, z=100).items():              # check get
            self.assertEqual(d.get(k, 100), v)
        self.assertIn(repr(d), [                                      # check repr
            type(d).__name__ + "({'c': 30}, {'a': 1, 'b': 2})",
            type(d).__name__ + "({'c': 30}, {'b': 2, 'a': 1})"
        ])

        for e in d.copy(), copy.copy(d):                               # check shallow copies
            self.assertEqual(d, e)
            self.assertEqual(d.maps, e.maps)
            self.assertIsNot(d, e)
            self.assertIsNot(d.maps[0], e.maps[0])
            for m1, m2 in zip(d.maps[1:], e.maps[1:]):
                self.assertIs(m1, m2)

        # check deep copies
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            e = pickle.loads(pickle.dumps(d, proto))
            self.assertEqual(d, e)
            self.assertEqual(d.maps, e.maps)
            self.assertIsNot(d, e)
            for m1, m2 in zip(d.maps, e.maps):
                self.assertIsNot(m1, m2, e)
        for e in [copy.deepcopy(d),
                  eval(repr(d))
                ]:
            self.assertEqual(d, e)
            self.assertEqual(d.maps, e.maps)
            self.assertIsNot(d, e)
            for m1, m2 in zip(d.maps, e.maps):
                self.assertIsNot(m1, m2, e)

        f = d.new_child()
        f['b'] = 5
        self.assertEqual(f.maps, [{'b': 5}, {'c':30}, {'a':1, 'b':2}])
        self.assertEqual(f.parents.maps, [{'c':30}, {'a':1, 'b':2}])   # check parents
        self.assertEqual(f['b'], 5)                                    # find first in chain