def testCommonAncestor(self):
bst = BinarySearchTree()
l = [8, 4, 2, 1, 3, 6, 5, 7, 12, 10, 9, 11, 14, 13, 15]
for d in l:
bst.insert(d)
self.assertEqual(bst.commonAncestor(4, 12), 8)
self.assertEqual(bst.commonAncestor(4, 10), 8)
self.assertEqual(bst.commonAncestor(4, 14), 8)
self.assertEqual(bst.commonAncestor(1, 15), 8)
