如何在间接参数化中注释request.param? [英] How can request.param be annotated in indirect parametrization?

问题描述

在间接参数化示例中，我想要键入提示 request.param 来指示特定类型，例如 str .

In the Indirect parametrization example I want to type hint request.param indicating a specific type, a str for example.

问题是因为 fixt 的参数必须为应该是(引用文档).

The problem is since the argument to fixt must be the request fixture there seems to be no way to indicate what type the parameters passed through the "optional param attribute" should be (quoting the documentation).

有哪些替代方案?也许在 fixt 文档字符串或 test_indirect 文档字符串中记录类型提示?

What are the alternatives? Perhaps documenting the type hint in the fixt docstring, or in the test_indirect docstring?

@pytest.fixture
def fixt(request):
    return request.param * 3

@pytest.mark.parametrize("fixt", ["a", "b"], indirect=True)
def test_indirect(fixt):
    assert len(fixt) == 3

推荐答案

到目前为止(版本6.2)， pytest 尚未为 param 提供任何类型提示.属性.如果您只需要键入 param ，而不管其他 FixtureRequest 字段和方法如何，都可以内联自己的impl存根:

As of now (version 6.2), pytest doesn't provide any type hint for the param attribute. If you need to just type param regardless of the rest of FixtureRequest fields and methods, you can inline your own impl stub:

from typing import TYPE_CHECKING


if TYPE_CHECKING:
    class FixtureRequest:
        param: str
else:
    from typing import Any
    FixtureRequest = Any


@pytest.fixture
def fixt(request: FixtureRequest) -> str:
    return request.param * 3

如果您想扩展 FixtureRequest 的现有类型，则存根会变得有些复杂:

If you want to extend existing typing of FixtureRequest, the stubbing gets somewhat more complex:

from typing import TYPE_CHECKING


if TYPE_CHECKING:
    from pytest import FixtureRequest as __FixtureRequest
    class FixtureRequest(__FixtureRequest):
        param: str
else:
    from pytest import FixtureRequest


@pytest.fixture
def fixt(request: FixtureRequest) -> str:
    return request.param * 3

理想情况下， pytest 将允许在 FixtureRequest 中使用通用的 param 类型，例如

Ideally, pytest would allow generic param types in FixtureRequest, e.g.

P = TypeVar("P")  # generic param type

class FixtureRequest(Generic[P]):
    def __init__(self, param: P, ...):
        ...

然后您会做

from pytest import FixtureRequest

@pytest.fixture
def fixt(request: FixtureRequest[str]) -> str:
    return request.param * 3

但是，不确定这种输入是否与当前 pytest 的代码库相符-我猜是由于某种原因而忽略了它...

Not sure, however, whether this typing is agreeable with the current pytest's codebase - I guess it was omitted for a reason...

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