使用间接参数化时，`fixture` 中的 `scope` 和 `parametrize` 中的 `scope` 之间的区别

Question

我想使用间接参数化，如 this answer and in pytest documentation 所示。

我希望能够设置范围，以便能够配置夹具是针对每个函数运行还是针对其中的许多函数一次。

但是我看到我可以在 fixture 装饰器上设置范围：

import pytest

@pytest.fixture(scope="function")
def fixt(request):
    return request.param * 3

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

或在 parametrize 装饰器上：

import pytest

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

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

或者两者同时进行：

import pytest

@pytest.fixture(scope="function")
def fixt(request):
    return request.param * 3

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

有什么区别，我应该在什么时候设置它们？

更新：

我测试了每一个，看看它们有何不同。

我用来测试的代码：

import pytest

scope_fixture="function"
scope_parametrize="module"

with open('scope_log.txt', 'a') as file:
    file.write(f'--------\n')
    file.write(f'{scope_fixture=}\n')
    file.write(f'{scope_parametrize=}\n')

@pytest.fixture(scope=scope_fixture)
def fixt(request):
    with open('scope_log.txt', 'a') as file:
        file.write(f'fixture ' + str(request.param)+'\n')
    return request.param * 3

@pytest.mark.parametrize("fixt", ["a", "b"], indirect=True, scope=scope_parametrize)
def test_indirect1(fixt):
    with open('scope_log.txt', 'a') as file:
        file.write(f'1 ' + str(fixt)+'\n')
    assert len(fixt) == 3

@pytest.mark.parametrize("fixt", ["a", "b"], indirect=True, scope=scope_parametrize)
def test_indirect2(fixt):
    with open('scope_log.txt', 'a') as file:
        file.write(f'2 ' + str(fixt)+'\n')
    assert len(fixt) == 3

结果：

scope_fixture=None
scope_parametrize=None
fixture a
1 aaa
fixture b
1 bbb
fixture a
2 aaa
fixture b
2 bbb
--------
scope_fixture='function'
scope_parametrize=None
fixture a
1 aaa
fixture b
1 bbb
fixture a
2 aaa
fixture b
2 bbb
--------
scope_fixture='module'
scope_parametrize=None
fixture a
1 aaa
2 aaa
fixture b
1 bbb
2 bbb
--------
scope_fixture=None
scope_parametrize='function'
fixture a
1 aaa
fixture b
1 bbb
fixture a
2 aaa
fixture b
2 bbb
--------
scope_fixture=None
scope_parametrize='module'
fixture a
1 aaa
2 aaa
fixture b
1 bbb
2 bbb
--------
scope_fixture='function'
scope_parametrize='module'
fixture a
1 aaa
2 aaa
fixture b
1 bbb
2 bbb
--------
scope_fixture='module'
scope_parametrize='module'
fixture a
1 aaa
2 aaa
fixture b
1 bbb
2 bbb
--------
scope_fixture='module'
scope_parametrize='function'
fixture a
1 aaa
fixture b
1 bbb
fixture a
2 aaa
fixture b
2 bbb
--------
scope_fixture='function'
scope_parametrize='function'
fixture a
1 aaa
fixture b
1 bbb
fixture a
2 aaa
fixture b
2 bbb

Answer 1

正如@Tzane 在评论中指出的那样，为 parametrize 设置范围会覆盖 fixtures 中设置的任何范围。

来自documentation：

scope (Optional[_ScopeName]) – If specified it denotes the scope of the parameters. The scope is used for grouping tests by parameter instances. It will also override any fixture-function defined scope, allowing to set a dynamic scope using test context or configuration.

使用间接参数化时，`fixture` 中的 `scope` 和 `parametrize` 中的 `scope` 之间的区别

Difference between `scope` in `fixture` and `scope` in `parametrize` when using indirect parametrization

python

python-3.x

pytest

fixtures

parametrized-testing