def test_find_maximum_value_tree_with_two_values():
one_value = BST([10, 2])
assert find_maximum_value(one_value) == 10
def test_find_maximum_value_right():
right = BST([1, 3, 5, 7, 9])
assert find_maximum_value(right) == 9
def test_find_maximum_value_tree_with_one_value():
one_value = BST([5])
assert find_maximum_value(one_value) == 5
def test_find_maximum_value_left():
left = BST([10, 8, 6, 4])
assert find_maximum_value(left) == 10
def test_find_maximum_value_balanced():
balanced = BST([10, 7, 3, 16, 12, 8, 20])
assert find_maximum_value(balanced) == 20
def test_max_none(capsys):
"""No output."""
a = BST()
assert find_maximum_value(a) is None
def test_max_unbalanced(tree):
"""Correct output order."""
tree.insert(4)
assert find_maximum_value(tree) == 16
def test_max(tree):
"""Correct output order."""
assert find_maximum_value(tree) == 16