def test_raises_expects_function_to_raise_error():
func = deal.raises(ZeroDivisionError)(lambda x: 1 / x)
with pytest.raises(ZeroDivisionError):
func(0)
func(2)
func = deal.raises(KeyError)(lambda x: 1 / x)
with pytest.raises(deal.RaisesContractError):
func(0)
def test_main(self):
func = deal.raises(ZeroDivisionError)(lambda x: 1 / x)
with self.subTest(text='good'):
with self.assertRaises(ZeroDivisionError):
func(0)
with self.subTest(text='good'):
func(2)
func = deal.raises(KeyError)(lambda x: 1 / x)
with self.subTest(text='error'):
with self.assertRaises(deal.RaisesContractError):
func(0)
# result is an index of items
deal.post(lambda result: result >= 0),
deal.ensure(lambda items, item, result: result < len(items)),
# element at this position matches item
deal.ensure(
lambda items, item, result: items[result] == item,
message='invalid match',
),
# element at this position is the first match
deal.ensure(
lambda items, item, result: not any(el == item
for el in items[:result]),
message='not the first match',
),
# LookupError will be raised if no elements found
deal.raises(LookupError),
deal.reason(LookupError, lambda items, item: item not in items),
# no side-effects
deal.has(),
)
@contract_for_index_of
def index_of(items: List[int], item: int) -> int:
for index, el in enumerate(items):
if el == item:
return index
raise LookupError
@pytest.mark.parametrize('case', deal.cases(index_of))