def test_match_function_constructor(self, Maybe):
x = Maybe.Just(42)
y = Maybe.Nothing
func = Maybe.match_fn(
just=lambda x: x * 2,
nothing=lambda: 0,
)
assert func(x) == 84
assert func(y) == 0
def test_match_fn_raises_error_on_non_exaustive_options(self, Maybe):
with pytest.raises(ValueError):
Maybe.match_fn(just=lambda x: x, )
with pytest.raises(ValueError):
Maybe.match_fn(
just=lambda x: x,
nothing=lambda: 0,
other=lambda: 0,
)
with pytest.raises(ValueError):
Maybe.match_fn(
ok=lambda x: x,
err=lambda: 0,
)