def test_swap_with_invalid_key(self):
d = {
'a': 1,
'b': 2,
'c': 3,
}
with self.assertRaises(KeyError):
_swap(d, 'a', 'd')
def test_swap_with_same_key(self):
d = {
'a': 1,
'b': 2,
}
_swap(d, 'a', 'a')
r = {
'a': 1,
'b': 2,
}
self.assertEqual(d, r)
def test_swap(self):
d = {
'a': 1,
'b': 2,
'c': 3,
}
_swap(d, 'a', 'b')
r = {
'a': 2,
'b': 1,
'c': 3,
}
self.assertEqual(d, r)
def swap(self, key1, key2):
"""
Swap items values at the given keys.
"""
_swap(self, key1, key2)