def test_traverse():
assert Container.of(42).traverse(None, Either.of).join().join() == 42
def test_fmap():
assert Container.of(21).fmap(lambda x: x * 2)._value == 42
def test_of():
assert Container.of(42)._value == 42
def test_sequence():
assert Container.of(Either.of(42)).sequence(None).join().join() == 42
def test_chain():
assert Container.of(21).fmap(lambda x: x * 2).join() == 42
def test_join():
assert Container.of(42).join() == 42
def test_ap():
f = lambda x: lambda y: x + y
c1 = Container.of(3)
c2 = Container.of(39)
assert Container.of(f).ap(c1).ap(c2)._value == 42