我制作了一个有趣的装饰器，可以像这样编写固定装置：
@fixture_taking_arguments
def dog(request, /, name, age=69):
return f"{name} the dog aged {age}"
在这里，/ 的左侧有其他灯具，右侧有使用以下参数提供的参数：
@dog.arguments("Buddy", age=7)
def test_with_dog(dog):
assert dog == "Buddy the dog aged 7"
这与函数参数的工作方式相同。如果您不提供age 参数，则使用默认参数69。如果你不提供name，或者省略dog.arguments 装饰器，你会得到常规的TypeError: dog() missing 1 required positional argument: 'name'。如果您有另一个带有参数name 的夹具，它不会与这个冲突。
也支持异步装置。
此外，这为您提供了一个不错的设置计划：
$ 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']
一个完整的例子：
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"
装饰器的代码：
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