mirror of
https://github.com/correl/typesafe-monads.git
synced 2024-11-22 03:00:16 +00:00
156 lines
3.9 KiB
Python
156 lines
3.9 KiB
Python
from __future__ import annotations
|
|
from typing import Callable
|
|
|
|
from monads.maybe import Maybe, Just, Nothing
|
|
from monads.result import Result, Ok, Err, safe
|
|
|
|
|
|
def test_bind_ok() -> None:
|
|
m: Result[int, str] = Ok(5)
|
|
increment: Callable[[int], Result[int, str]] = lambda x: Ok(x + 1)
|
|
assert Ok(6) == m.bind(increment)
|
|
|
|
|
|
def test_bind_err() -> None:
|
|
m: Result[int, str] = Err("oops")
|
|
increment: Callable[[int], Result[int, str]] = lambda x: Ok(x + 1)
|
|
assert Err("oops") == m.bind(increment)
|
|
|
|
|
|
def test_apply_ok_to_ok() -> None:
|
|
m: Result[int, str] = Ok(5)
|
|
increment: Callable[[int], int] = lambda x: x + 1
|
|
assert Ok(6) == m.apply(Result.pure(increment))
|
|
|
|
|
|
def test_apply_ok_to_err() -> None:
|
|
m: Result[int, str] = Err("oops")
|
|
increment: Callable[[int], int] = lambda x: x + 1
|
|
assert Err("oops") == m.apply(Result.pure(increment))
|
|
|
|
|
|
def test_apply_err_to_ok() -> None:
|
|
m: Result[int, str] = Ok(5)
|
|
f: Result[Callable[[int], int], str] = Err("oops")
|
|
assert Err("oops") == m.apply(f)
|
|
|
|
|
|
def test_apply_err_to_err() -> None:
|
|
m: Result[int, str] = Err("oops")
|
|
f: Result[Callable[[int], int], str] = Err("oops")
|
|
assert Err("oops") == m.apply(f)
|
|
|
|
|
|
def test_ok_withdefault() -> None:
|
|
m: Result[int, str] = Ok(5)
|
|
assert 5 == m.withDefault(0)
|
|
|
|
|
|
def test_err_withdefault() -> None:
|
|
m: Result[int, str] = Err("oops")
|
|
assert 0 == m.withDefault(0)
|
|
|
|
|
|
def test_map() -> None:
|
|
result: Result[int, str] = Ok(5)
|
|
mapped: Result[str, str] = result.map(str)
|
|
assert "5" == mapped.withDefault("0")
|
|
|
|
|
|
def test_map_infix() -> None:
|
|
result: Result[int, str] = Ok(5)
|
|
mapped: Result[str, str] = result * str
|
|
assert "5" == mapped.withDefault("0")
|
|
|
|
|
|
def test_map_error_err() -> None:
|
|
m: Result[int, str] = Err("oops")
|
|
assert Err(4) == m.mapError(len)
|
|
|
|
|
|
def test_map_error_ok() -> None:
|
|
m: Result[int, str] = Ok(123)
|
|
assert Ok(123) == m.mapError(len)
|
|
|
|
|
|
def test_bind() -> None:
|
|
result: Result[int, str] = Ok(5)
|
|
incremented: Result[int, str] = result.bind(lambda x: Ok(x + 1))
|
|
assert 6 == incremented.withDefault(0)
|
|
|
|
|
|
def test_bind_infix() -> None:
|
|
result: Result[int, str] = Ok(5)
|
|
incremented: Result[int, str] = result >> (lambda x: Ok(x + 1))
|
|
assert 6 == incremented.withDefault(0)
|
|
|
|
|
|
def test_pipeline() -> None:
|
|
class Frobnicator(object):
|
|
@classmethod
|
|
def create(cls, config: dict) -> Result[Frobnicator, str]:
|
|
return Ok(cls())
|
|
|
|
def dostuff(self) -> Result[list, str]:
|
|
return Ok(["a", "b", "c", "d"])
|
|
|
|
def load_config() -> Result[dict, str]:
|
|
return Ok({"foo": "bar"})
|
|
|
|
result: Result[int, str] = (
|
|
load_config()
|
|
>> Frobnicator.create
|
|
>> Frobnicator.dostuff
|
|
>> (lambda res: Ok(len(res)))
|
|
)
|
|
assert 4 == result.withDefault(0)
|
|
|
|
|
|
def test_unsafe_wrapped_function_returns_error() -> None:
|
|
error: Exception = Exception("oops")
|
|
|
|
@safe
|
|
def unsafe(x: int) -> int:
|
|
if x > 5:
|
|
raise error
|
|
else:
|
|
return x + 1
|
|
|
|
result: Result[int, Exception] = unsafe(10)
|
|
assert Err(error) == result
|
|
|
|
|
|
def test_safe_wrapped_function_returns_ok() -> None:
|
|
error: Exception = Exception("oops")
|
|
|
|
@safe
|
|
def unsafe(x: int) -> int:
|
|
if x > 5:
|
|
raise error
|
|
else:
|
|
return x + 1
|
|
|
|
result: Result[int, Exception] = unsafe(5)
|
|
assert Ok(6) == result
|
|
|
|
|
|
def test_from_just() -> None:
|
|
m: Maybe[int] = Just(6)
|
|
result: Result[int, str] = Result.fromMaybe(m, "error")
|
|
assert Ok(6) == result
|
|
|
|
|
|
def test_from_nothing() -> None:
|
|
m: Maybe[int] = Nothing()
|
|
result: Result[int, str] = Result.fromMaybe(m, "error")
|
|
assert Err("error") == result
|
|
|
|
|
|
def test_ok_to_maybe() -> None:
|
|
result: Result[int, str] = Ok(6)
|
|
assert Just(6) == result.toMaybe()
|
|
|
|
|
|
def test_err_to_maybe() -> None:
|
|
result: Result[int, str] = Err("error")
|
|
assert Nothing() == result.toMaybe()
|