Compares the two trees defined by Nodes a and b and returns true if they are equal in structure and in value and false otherwise.

node_compare.py

if a == b:
        return True
    if a is None or b is None:
        return False
    if a.val != b.val:
        return False
    return compare(a.left, b.left) and compare(a.right, b.right)

test_node_compare.py

import unittest
from node_compare import compare, Node

a_node = Node(1, None, None)
b_node = Node(1, None, None)
c_node = Node(2, None, None)

d_node = Node(1, Node(1, None, None), None)
e_node = Node(1, Node(1, None, None), None)


f_node = Node(1, Node(1, None, Node(1, None, None)), None)
g_node = Node(1, Node(1, None, Node(1, None, None)), None)

class Test(unittest.TestCase):

    def test_should_return_true_for_equal_nodes(self):
        self.assertTrue(compare(a_node, b_node))
    def test_should_return_false_for_non_equal_nodes(self):
        self.assertFalse(compare(a_node, c_node))
    def test_should_handle_depth_of_one(self):
        self.assertFalse(compare(d_node, None))
    def test_should_handle_depth_of_two(self):
        self.assertTrue(compare(f_node, g_node))

if __name__ == '__main__':
    unittest.main()