def test_add(self):
bst = BST()
bst.add(10)
assert bst.root.val == 10
assert bst.is_empty() is False
assert bst.size == 1
assert bst.levels == 1
assert bst.serialize() == '10'
assert bst.level_order() == [[10]]
assert bst.pre_order() == [10]
assert bst.in_order() == [10]
assert bst.post_order() == [10]
assert bst == BST(serialize='10')
bst.add(1)
assert bst.root.val == 10
assert bst.is_empty() is False
assert bst.size == 2
assert bst.levels == 2
assert bst.serialize() == '10,1,#'
assert bst.level_order() == [[10], [1]]
assert bst.pre_order() == [10, 1]
assert bst.in_order() == [1, 10]
assert bst.post_order() == [1, 10]
bst.add(20)
assert bst.root.val == 10
assert bst.is_empty() is False
assert bst.size == 3
assert bst.levels == 2
assert bst.serialize() == '10,1,20'
assert bst.level_order() == [[10], [1, 20]]
assert bst.pre_order() == [10, 1, 20]
assert bst.in_order() == [1, 10, 20]
assert bst.post_order() == [1, 20, 10]
bst.add(5)
bst.add(15)
assert bst.root.val == 10
assert bst.is_empty() is False
assert bst.size == 5
assert bst.levels == 3
assert bst.serialize() == '10,1,20,#,5,15,#'
assert bst.level_order() == [[10], [1, 20], [5, 15]]
assert bst.pre_order() == [10, 1, 5, 20, 15]
assert bst.in_order() == [1, 5, 10, 15, 20]
assert bst.post_order() == [5, 1, 15, 20, 10]
def test_empty_tree(self):
bst = BST()
assert bst.root is None
assert bst.is_empty() is True
assert bst.size == 0
assert bst.levels == 0
assert bst.__repr__() == "BST(serialize='')"
assert bst.serialize() == ''
assert bst.level_order() == []
assert bst.pre_order() == []
assert bst.in_order() == []
assert bst.post_order() == []
assert bst == BST()
