def test_whole_key_as_prefix(self):
trie = Trie()
trie.add('foobar', 1)
assert trie.has_prefix('foobar')
def test_key_does_not_exist(self):
trie = Trie()
assert not trie.has_prefix('foobar')
def test_prefix_exists(self):
trie = Trie()
trie.add('foobar', 1)
assert trie.has_prefix('foo')