def test_get_predecessor(self):
n1 = Node(2)
n2 = Node(3)
n3 = Node(4)
n1.add_right(n2)
n2.add_left(n3)
self.assertEqual(n3.getPredecessor(), n1)
def test_get_predecessor_None(self):
n1 = Node(2)
self.assertIsNone(n1.getPredecessor())
def test_get_predecessor_basic_2(self):
n1 = Node(2)
n2 = Node(3)
n1.add_right(n2)
self.assertEqual(n2.getPredecessor(), n1)
def test_get_predecessor_basic(self):
n1 = Node(2)
n2 = Node(3)
n1.add_left(n2)
self.assertEqual(n1.getPredecessor(), n2)
self.assertIsNone(n2.getPredecessor())
