def test_should_add_child_node_to_an_existent_node():
trie_node = TrieNode('a')
b_node = trie_node.add_child_node('b', True)
assert trie_node.has_children()
assert trie_node.get_child_node('b') is not None
assert b_node.char == 'b'
assert b_node.is_last_node
assert b_node.has_children() is False
def test_should_trie_node_has_a_child_node():
a_trie_node = TrieNode('a')
a_trie_node.add_child_node('b')
assert a_trie_node.get_child_node('b') is not None
def test_should_get_or_add_child_node():
trie_node = TrieNode('a')
b_node = trie_node.get_or_add_child_node('b')
assert trie_node.get_child_node('b') is not None
assert trie_node.get_or_add_child_node('b') == b_node
def test_should_get_child_node():
trie_node = TrieNode('a')
trie_node.add_child_node('b')
b_node = trie_node.get_child_node('b')
assert b_node.char == 'b'