def test_contains_three_right():
tree = BinarySearchTree()
tree.add(20)
tree.add(30)
tree.add(10)
expected = True
actual = tree.contains(30)
assert actual == expected
def test_contains_lots():
tree = BinarySearchTree()
tree.add(20)
tree.add(15)
tree.add(24)
tree.add(16)
tree.add(14)
tree.add(22)
tree.add(30)
expected = True
actual = tree.contains(16)
assert actual == expected
def test_contains_one():
tree = BinarySearchTree()
tree.add(20)
expected = True
actual = tree.contains(20)
assert actual == expected