public void IsSameTree_BothNull_ShouldReturnTrue()
        {
            TreeNode tree        = null;
            TreeNode second_tree = null;

            var result = IsSameTreeImplementation.IsSameTree(tree, second_tree);

            Assert.True(result);
        }
        public void IsSameTree_OneTreeIsNull_ShouldReturnFalse()
        {
            var tree = new TreeNode(5);

            tree.left  = new TreeNode(3);
            tree.right = new TreeNode(9);
            TreeNode second_tree = null;

            var result = IsSameTreeImplementation.IsSameTree(tree, second_tree);

            Assert.False(result);
        }
        public void IsSameTree_TreesAreDifferent_ShouldReturnFalse()
        {
            var tree = new TreeNode(5);

            tree.left  = new TreeNode(3);
            tree.right = new TreeNode(9);
            var second_tree = new TreeNode(5);

            second_tree.left  = new TreeNode(9);
            second_tree.right = new TreeNode(3);

            var result = IsSameTreeImplementation.IsSameTree(tree, second_tree);

            Assert.False(result);
        }