def test_circular():
    print("Test is_circular: ", end="")
    node = Node()
    node.next = node
    res = is_circular(node)
    if res:
        print("OK", end="\n")
    else:
        print("FAIL -> Node -> ma vracet True, vracite False", end="\n")
    print("Test is_circular 2: ", end="")
    node2 = Node()
    node.next = node2
    node3 = Node()
    node2.next = node3
    node3.next = node
    res = is_circular(node)
    if res:
        print("OK", end="\n")
    else:
        print("FAIL -> Node -> Node2 -> Node3 -> ma vracet True, vracite False", end="\n")
    print("Test is_circular 3: ", end="")
    node3.next = None
    res = is_circular(node)
    if res:
        print("FAIL -> Node -> Node2 -> Node3 ma vracet False, vracite True", end="\n")
    else:
        print("OK", end="\n")


def test_get_length():
    print("Test get_length: ", end="")
    node = Node()
    node.next = None
    res = get_length(node)
    if res == 1:
        print("OK", end="\n")
    else:
        print("FAIL -> Node ma vracet 1, vy vracite %d" % res, end="\n")
    print("Test get_length 2: ", end="")
    node2 = Node()
    node3 = Node()
    node4 = Node()
    node.next = node2
    node2.next = node3
    node3.next = node4
    node4.next = node
    res = get_length(node)
    if res == 4:
        print("OK", end="\n")
    else:
        print("FAIL -> Node, Node2, Node3, Node4 -> ma vracet 4, vy vracite %d" % res, end="\n")
    print("Test get_length 3: ", end="")
    node4.next = None
    res = get_length(node)
    if res == 4:
        print("OK", end="\n")
    else:
        print("FAIL -> Node1, Node2, Node3, Node4 ma vracet 4, vy vracite %d" % res, end="\n")


def test_calculate_opposites():
    pass


if __name__ == '__main__':
    test_circular()
    test_get_length()
    test_calculate_opposites()