私はこのようなフィクスチャを書くことができる面白いデコレータを作りました：
@fixture_taking_arguments
def dog(request, /, name, age=69):
return f"{name} the dog aged {age}"
ここでは、左側に/他のフィクスチャーがあり、右側には次を使用して提供されるパラメーターがあります。
@dog.arguments("Buddy", age=7)
def test_with_dog(dog):
assert dog == "Buddy the dog aged 7"
これは、関数の引数が機能するのと同じように機能します。age引数を指定しない場合69、代わりにデフォルトのが使用されます。指定しない場合name、またはdog.argumentsデコレータを省略した場合は、通常のものが得られますTypeError: dog() missing 1 required positional argument: 'name'。引数を取る別のフィクスチャがある場合name、それはこのフィクスチャと競合しません。
非同期フィクスチャもサポートされています。
さらに、これはあなたに素晴らしいセットアッププランを与えます：
$ pytest test_dogs_and_owners.py --setup-plan
SETUP F dog['Buddy', age=7]
...
SETUP F dog['Champion']
SETUP F owner (fixtures used: dog)['John Travolta']
完全な例：
from plugin import fixture_taking_arguments
@fixture_taking_arguments
def dog(request, /, name, age=69):
return f"{name} the dog aged {age}"
@fixture_taking_arguments
def owner(request, dog, /, name="John Doe"):
yield f"{name}, owner of {dog}"
@dog.arguments("Buddy", age=7)
def test_with_dog(dog):
assert dog == "Buddy the dog aged 7"
@dog.arguments("Champion")
class TestChampion:
def test_with_dog(self, dog):
assert dog == "Champion the dog aged 69"
def test_with_default_owner(self, owner, dog):
assert owner == "John Doe, owner of Champion the dog aged 69"
assert dog == "Champion the dog aged 69"
@owner.arguments("John Travolta")
def test_with_named_owner(self, owner):
assert owner == "John Travolta, owner of Champion the dog aged 69"
デコレーターのコード：
import pytest
from dataclasses import dataclass
from functools import wraps
from inspect import signature, Parameter, isgeneratorfunction, iscoroutinefunction, isasyncgenfunction
from itertools import zip_longest, chain
_NOTHING = object()
def _omittable_parentheses_decorator(decorator):
@wraps(decorator)
def wrapper(*args, **kwargs):
if not kwargs and len(args) == 1 and callable(args[0]):
return decorator()(args[0])
else:
return decorator(*args, **kwargs)
return wrapper
@dataclass
class _ArgsKwargs:
args: ...
kwargs: ...
def __repr__(self):
return ", ".join(chain(
(repr(v) for v in self.args),
(f"{k}={v!r}" for k, v in self.kwargs.items())))
def _flatten_arguments(sig, args, kwargs):
assert len(sig.parameters) == len(args) + len(kwargs)
for name, arg in zip_longest(sig.parameters, args, fillvalue=_NOTHING):
yield arg if arg is not _NOTHING else kwargs[name]
def _get_actual_args_kwargs(sig, args, kwargs):
request = kwargs["request"]
try:
request_args, request_kwargs = request.param.args, request.param.kwargs
except AttributeError:
request_args, request_kwargs = (), {}
return tuple(_flatten_arguments(sig, args, kwargs)) + request_args, request_kwargs
@_omittable_parentheses_decorator
def fixture_taking_arguments(*pytest_fixture_args, **pytest_fixture_kwargs):
def decorator(func):
original_signature = signature(func)
def new_parameters():
for param in original_signature.parameters.values():
if param.kind == Parameter.POSITIONAL_ONLY:
yield param.replace(kind=Parameter.POSITIONAL_OR_KEYWORD)
new_signature = original_signature.replace(parameters=list(new_parameters()))
if "request" not in new_signature.parameters:
raise AttributeError("Target function must have positional-only argument `request`")
is_async_generator = isasyncgenfunction(func)
is_async = is_async_generator or iscoroutinefunction(func)
is_generator = isgeneratorfunction(func)
if is_async:
@wraps(func)
async def wrapper(*args, **kwargs):
args, kwargs = _get_actual_args_kwargs(new_signature, args, kwargs)
if is_async_generator:
async for result in func(*args, **kwargs):
yield result
else:
yield await func(*args, **kwargs)
else:
@wraps(func)
def wrapper(*args, **kwargs):
args, kwargs = _get_actual_args_kwargs(new_signature, args, kwargs)
if is_generator:
yield from func(*args, **kwargs)
else:
yield func(*args, **kwargs)
wrapper.__signature__ = new_signature
fixture = pytest.fixture(*pytest_fixture_args, **pytest_fixture_kwargs)(wrapper)
fixture_name = pytest_fixture_kwargs.get("name", fixture.__name__)
def parametrizer(*args, **kwargs):
return pytest.mark.parametrize(fixture_name, [_ArgsKwargs(args, kwargs)], indirect=True)
fixture.arguments = parametrizer
return fixture
return decorator