def test_functor():
a = Some(2)
n = Nil()
actual = a.map(lambda x: x + 2)
expected = Some(4)
assert actual == expected
actual = n.map(lambda x: x + 2)
expected = Nil()
assert actual == expected
def test_monad_flatten():
a = Some(Some(3))
actual = a.flatten()
expected = Some(3)
assert actual == expected
a = Some(Nil())
actual = a.flatten()
expected = Nil()
assert actual == expected
a = Nil()
actual = a.flatten()
expected = Nil()
assert actual == expected
def test_some(obj):
some = Some(obj)
assert some.value == obj
a_obj = some.match(
some=lambda x: x,
nil=None
)
assert a_obj == obj
resp = some.match(
some=12345,
nil=None
)
assert resp == 12345
def test_applicative_ap():
a = Some(3)
n = Nil()
fn = Some(lambda x: x - 1)
actual = fn.ap(a)
expected = Some(2)
assert actual == expected
actual = fn.ap(n)
expected = Nil()
assert actual == expected
fn = Nil()
actual = fn.ap(a)
expected = Nil()
assert actual == expected
def test_monad_flat_map():
a = Some(2)
actual = a.flat_map(lambda x: Some(x + 3))
expected = Some(5)
assert actual == expected
actual = a.flat_map(lambda _: Nil())
expected = Nil()
assert actual == expected
n = Nil()
actual = n.flat_map(lambda x: Some(x + 1))
expected = Nil()
assert actual == expected
def test_semigroup():
a = Some(1)
b = Some(2)
n = Nil()
actual = a.combine(b)
expected = Some(3)
assert actual == expected
actual = a + b
assert actual == expected
actual = a.combine(n)
expected = n
assert actual == expected
actual = n.combine(b)
expected = n
assert actual == expected
actual = n.combine(n)
expected = n
assert actual == expected
def test_applicative_pure():
actual = Option.pure(1)
expected = Some(1)
assert actual == expected
def test_monoid():
assert Option.unit() == Nil()
assert Some.unit() == Nil()
assert Nil.unit() == Nil()