使用函数参数化 pytest

Question

我有许多不同的自定义转换器函数，并且想运行对所有这些函数进行简单测试（例如打印出转换器）。我可以为每个函数编写单独的测试，但认为一定有更简单的方法。

我看过参数化测试但得到：TypeError: 'function' object is not iterable

@pytest.fixture
def list_transformers(self):
    list_transformers = [
        TransformerOne(column='a'),
        TransformerTwo(column='a')
    ]
    return list_trasformers

@pytest.mark.parametrize("transformer", list_transformers)
    def test_print(self, transformer):
        tf_type = transformer[0]
        params = transformer[1]
        tf = tf_type(**params)
        print(tf)

我认为这是因为转换器函数没有返回可迭代的东西。我应该以不同的方式解决这个问题吗？

Answer 1

为什么不直接将列表传递给装饰器：

@pytest.mark.parametrize("transformer", [TransformerOne(column='a'), TransformerTwo(column='a')])
def test_print(self, transformer):
    ...

Answer 2

Using fixtures in pytest.mark.parametrize 尚未得到完全支持。

除了使用 @pytest.mark.parametrize，您还可以使用另一种类型的参数化测试，即通过 pytest_generate_tests.

import pytest


def pytest_generate_tests(metafunc):
    if "transformer" in metafunc.fixturenames:
        list_transformers = [
            'This is a',
            'While that is b',
        ]
        metafunc.parametrize("transformer", list_transformers)


def test_print(transformer):
    print(transformer)

输出：

$ pytest -q -rP
..                                                                                                                                                                                                  [100%]
================================================================================================= PASSES ==================================================================================================
__________________________________________________________________________________________ test_print[This is a] __________________________________________________________________________________________
------------------------------------------------------------------------------------------ Captured stdout call -------------------------------------------------------------------------------------------
This is a
_______________________________________________________________________________________ test_print[While that is b] _______________________________________________________________________________________
------------------------------------------------------------------------------------------ Captured stdout call -------------------------------------------------------------------------------------------
While that is b
2 passed in 0.07s

Answer 3

pytest.mark.parametrize() 的第二个参数必须是迭代器而不是函数引用。

像这样： @pytest.mark.parametrize("transformer", list_transformers())

或 @pytest.mark.parametrize("transformer", [TransformerOne(column='a'), TransformerTwo(column='a')])

使用函数参数化 pytest

Parameterize a pytest with functions

python

pytest