def test_bool():
assert bool(Failure(True)) is False
assert bool(Success(False)) is True
for n in test_range:
assert bool(Failure(n)) is False
assert bool(Success(n)) is True
assert bool(unit(n)) is True
def test_ftry_action():
inc = lambda n: n + 1
dec = lambda n: n - 1
act = ftry(inc)
assert act(Failure(1)) == 2
assert act(Success(1)) == 1
act = ftry(failure_handler=inc, success_handler=dec)
assert act(Failure(1)) == 2
assert act(Success(1)) == 0
def test_failsafe_decorator_combined():
@failsafe(predicate=bool, failure_on_value=42)
def wrap(x):
return x
assert wrap(True) == Success(True)
assert wrap(False) == Failure(False)
assert wrap('something') == Success('something')
assert wrap('') == Failure('')
assert wrap([False]) == Success([False])
assert wrap([]) == Failure([])
assert wrap(1) == Success(1)
assert wrap(0) == Failure(0)
assert wrap(None) == Failure(None)
assert wrap(42) == Failure(42)
def test_recover():
result = Failure(0).recover(lambda v: v + 1)
assert result == 1
result = Success(10).recover(lambda v: v + 1)
assert isinstance(result, Success)
assert result.value == 10
def test_fmap_functor_laws():
identity = lambda a: a
f = lambda a: a + 1
g = lambda a: a * 2
f_g = lambda n: f(g(n))
for n in test_range:
ft = unit(n)
# fmap id == id
assert ft.fmap(identity) == identity(ft)
# fmap (f . g) == fmap f . fmap g
assert ft.fmap(f_g) == ft.fmap(g).fmap(f)
value = 42
l = Failure('Something wrong.')
r = Success(value)
assert l.fmap(f) is l
assert r.fmap(f) == Success(f(42))
def test_ordering():
with pytest.raises(TypeError):
Failure(1) < 1
with pytest.raises(TypeError):
Success(1) < 1
for n in test_range:
assert (Failure(n) < Failure(n)) is False
assert Failure(n) > Failure(n - 1)
assert Failure(n) < Failure(n + 1)
assert (Success(n) < Success(n)) is False
assert Success(n) > Success(n - 1)
assert Success(n) < Success(n + 1)
assert Failure(n) < Success(n)
def test_compare():
for n in test_range:
assert Failure(n) == Failure(n)
assert Success(n) == Success(n)
assert Failure(n) != Success(n)
def test_match_failure_and_success():
assert Failure(0).match(lambda v: v + 1, lambda v: v / 2) == 1
assert Success(10).match(lambda v: v + 1, lambda v: v / 2) == 5
def test_match_failure_only():
assert Failure(0).match(lambda v: v + 1) == 1
assert Success(10).match(lambda v: v + 1) == 10