def test_removal():
bst = BinarySearchTree()
bst.add(2)
bst.add(4)
bst.add(55)
assert bst.size == 3
bst.remove(4)
assert bst.size == 2
assert bst.root.right.data == 55
def main():
# creating a binary search tree
data = [17, 13, 10, 15, 4, 11, 16, 21, 24, 23, 27, 25, 26]
bst = BinarySearchTree(data)
print(bst.breadth_first_list())
# Removing a few items...
print('\nDeleting a few items...')
bst.remove(4)
bst.remove(10)
bst.remove(27)
bst.remove(13)
print(bst.breadth_first_list())
print("\nadding 45 to BST...")
bst.add(45)
print(bst.breadth_first_list())
print('\nTHe height of the tree :', bst.height)
print('\nBST contains 45:', bst.contains(45))