def test_single(self):
     self.assertEqual(1, solution(Node(1)))
 def test_combined_with_left(self):
     self.assertEqual(3, solution(Node(1, left=Node(2))))
 def test_sample(self):
     self.assertEqual(
         12,
         solution(
             Node(-5,
                  left=Node(1),
                  right=Node(7,
                             left=Node(2),
                             right=Node(3)))
         )
     )
     self.assertEqual(
         6,
         solution(
             Node(
                 2,
                 left=Node(2),
                 right=Node(-3,
                            left=Node(5),
                            right=Node(1))
             )
         )
     )
     self.assertEqual(
         21,
         solution(
             Node(-1,
                  left=Node(2,
                            left=Node(7,
                                      left=Node(-1)),
                            right=Node(3,
                                       left=Node(9), right=Node(-6))),
                  right=Node(3,
                             left=Node(4), right=Node(0)))
         )
     )
 def test_subtree(self):
     self.assertEqual(33, solution(Node(-1, left=Node(30, right=Node(3)))))
 def test_only_root(self):
     self.assertEqual(42, solution(Node(42, left=Node(-1), right=Node(-2))))
 def test_only_right(self):
     self.assertEqual(10, solution(Node(6, right=Node(4), left=Node(-1))))
 def test_through_root(self):
     self.assertEqual(6, solution(Node(1, left=Node(2), right=Node(3))))