def test_node_delete_child(self):
"""
Test TrieNode.delete_child method
"""
# add children
node = TrieNode()
children = [TrieNode() for i in range(len(string.ascii_lowercase))]
node.children = children
# ensure all children are deleted
for i, letter in enumerate(string.ascii_lowercase):
self.assertIsNotNone(node.children[i])
node.delete_child(letter)
self.assertIsNone(node.children[i])
self.assertTrue(node.empty())
