def test_rescue_nothing():
"""Ensures that rescue works for Nothing container."""
def factory(arg) -> Maybe[int]:
return Some(1)
bound = Nothing.rescue(factory)
bound2 = Nothing.rescue(lambda _: Some(1))
assert bound == bound2
def test_is_compare():
"""Ensures that `is` operator works correctly."""
some_container = Some(1)
assert Nothing.bind(lambda state: state) is Nothing
assert some_container.rescue(lambda: Some('fix')) is some_container
assert some_container is not Some(1)
def test_bind_optional():
"""Ensures that bind_optional works correctly."""
def factory(inner_value: int) -> Optional[int]:
return inner_value if inner_value else None
assert Some(1).bind_optional(factory) == Some(1)
assert Some(0).bind_optional(factory) == Nothing
assert Nothing.bind_optional(factory) == Nothing
def test_bind_nothing():
"""Ensures that left identity works for Nothing container."""
def factory(inner_value) -> Maybe[int]:
return Some(1)
bound = Nothing.bind(factory)
assert bound == Nothing
assert str(bound) == '<Nothing>'
def _maybe_pipeline(number: int) -> Maybe[int]:
first: int = Some(number).unwrap() if number else Nothing.unwrap()
return Some(first + number)
def test_unwrap_failure():
"""Ensures that unwrap works for Nothing container."""
with pytest.raises(UnwrapFailedError):
assert Nothing.unwrap()
def test_nothing_value():
"""Ensures that value is fetch correctly from the Nothing."""
assert Nothing.value_or(default_value=1) == 1
def test_equals():
"""Ensures that ``.equals`` method works correctly."""
inner_value = 1
assert Some(inner_value).equals(Some(inner_value))
assert Nothing.equals(Nothing)
def test_not_equals():
"""Ensures that ``.equals`` method works correctly."""
assert not Some(1).equals(Nothing)
assert not Some(1).equals(Some(0))
assert not Nothing.equals(Some(1))
def test_fix_nothing():
"""Ensures that fix works for Nothing container."""
assert Nothing.fix(lambda _: None) == Nothing
assert Nothing.fix(lambda _: 1) == Some(1)
def test_map_nothing():
"""Ensures that map works for Nothing container."""
assert Nothing.map(str) == Nothing
def test_unwrap_failure_from_failure():
"""Ensures that failure works for Nothing container."""
assert Nothing.failure() is None # type: ignore
def test_unwrap_failure():
"""Ensures that unwrap works for Nothing container."""
assert Nothing.failure() is None