python - 类型错误 : missing 1 required positional argument while using pytest fixture

Question

这个问题在这里已经有了答案:





passing a py.test fixture between test files in a module

(1 个回答)


5 个月前关闭。




我已经在一个文件中编写了我的测试类，我正在尝试使用 pytest fixtures这样我就不必在每个测试函数中创建相同的输入数据。下面是最小的工作示例。

import unittest
import pytest

@pytest.fixture
def base_value():
    return 5

class Test(unittest.TestCase):

    def test_add_two(self, base_value):
        result = base_value + 2
        self.assertEqual(result, 7, "Result doesn't match")

但是，当我使用 pytest-3 对此进行测试时，出现以下错误:

TypeError: test_add_two() missing 1 required positional argument:'base_value'

这让我感到困惑，因为 base_value 明确作为 test_add_two 的参数之一给出。 .任何帮助都受到高度赞赏。

Answer 1

这是因为你在混pytest和 unittest .尝试

@pytest.fixture
def base_value():
    return 5


class Test:
    def test_add_two(self, base_value):
        result = base_value + 2
        assert result == 7, "Result doesn't match"

如果失败，错误将是

def test_add_two(self, base_value):
        result = base_value + 2
>       assert result == 8, "Result doesn't match"
E       AssertionError: Result doesn't match
E       assert 7 == 8

但是 pytest 与 unittest 不兼容吗？
仅在有限的基础上。来自 Pytest unittest.TestCase Support

pytest features in unittest.TestCase subclasses The following pytestfeatures work in unittest.TestCase subclasses:

• Marks: skip, skipif, xfail;
• Auto-use fixtures;

The following pytest features do not work, and probably never will dueto different design philosophies:

• Fixtures (except for autouse fixtures, see below);
• Parametrization;
• Custom hooks;

Third party plugins may or may not work well, depending on the pluginand the test suite.