def __call__(self, user_id: int) -> IO[Result[float, Exception]]:
"""Fetches `UserProfile` TypedDict from foreign API."""
return flow(
user_id,
self._make_request,
IO.lift(bind(self._parse_json)),
)
from returns.maybe import Nothing, Some
from returns.result import Failure, Success
def _success_case(state: int) -> int:
return state + 1
def _failed_case(_) -> int:
return 0
_result_converter = coalesce_result(_success_case, _failed_case)
_maybe_converter = coalesce_maybe(_success_case, _failed_case)
_ioresult_converter = coalesce_ioresult(
IO.lift(_success_case),
IO.lift(_failed_case),
)
def test_coalesce_result():
"""Ensures that `coalesce` is always returning the correct type."""
assert _result_converter(Success(1)) == 2
assert _result_converter(Failure(1)) == 0
def test_coalesce_ioresult():
"""Ensures that `coalesce` is always returning the correct type."""
assert _ioresult_converter(IOSuccess(1)) == IO(2)
assert _ioresult_converter(IOFailure(1)) == IO(0)
def test_lift_io():
"""Ensures that functions can be composed and return type is correct."""
lifted = IO.lift(_first)
assert lifted(IO(1)) == IO('2')
