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(sorted(d.items()),
sorted(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(sorted(d.items()),
sorted(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)
_ChainMap = ChainMap
for e in [pickle.loads(pickle.dumps(d)),
copy.deepcopy(d),
eval(repr(d))
]: # check deep copies
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
self.assertEqual(f.parents['b'], 2) # look beyond maps[0]
def test_dict_coercion(self):
d = ChainMap(dict(a=1, b=2), dict(b=20, c=30))
self.assertEqual(dict(d), dict(a=1, b=2, c=30))
self.assertEqual(dict(d.items()), dict(a=1, b=2, c=30))
def test_bool(self):
self.assertFalse(ChainMap())
self.assertFalse(ChainMap({}, {}))
self.assertTrue(ChainMap({1: 2}, {}))
self.assertTrue(ChainMap({}, {1: 2}))
def test_contructor(self):
self.assertEqual(ChainMap().maps, [{}]) # no-args --> one new dict
self.assertEqual(ChainMap({1: 2}).maps, [{1: 2}]) # 1 arg --> list