Py.test:对类中的测试用例进行参数化 [英] Py.test: parametrize test cases from classes

问题描述

我目前正在关注这个 py.test 示例，当我不这样做时它会成功使用类，但是当我将测试用例引入类时我失败了.

I'm currently following this py.test example and it works out when I do not use classes, however when I introduce test cases into classes I am failing.

我设法写的最小的情况如下:

The smallest case I managed to write is the following:

import unittest

import pytest

class FixtureTestCase(unittest.TestCase):

    @pytest.mark.parametrize("test_input,expected", [
    ("3+5", 8),
    ("2+4", 6),
    ("6*9", 42),
    ])
    def test_1(self, a, b):
        self.assertEqual(a, b)

不幸的是当我执行时

  py.test  test_suite.py

我收到错误消息:

  TypeError: test_1() takes exactly 3 arguments (1 given)

如何才能生成一组 test_1 测试?

How can I do in order to generate a battery of test_1 tests?

推荐答案

如果你从 unittest.TestCase 继承，你的测试方法不能有额外的参数.如果您只是从 object 子类化，它会起作用(尽管您必须使用常规的 assert 语句而不是 TestCase.assertEqual 方法.

If you subclass from unittest.TestCase, your test methods cannot have additional arguments. If you simply subclass from object, it will work (though you'll have to use regular assert statements instead of the TestCase.assertEqual methods.

import unittest

import pytest

class TestCase(object):

    @pytest.mark.parametrize("test_input,expected", [
    ("3+5", 8),
    ("2+4", 6),
    ("6*9", 42),
    ])
    def test_1(self, a, b):
        assert eval(a) == b

不过，在这一点上，它有点引出了一个问题，为什么您使用类而不是仅仅定义函数，因为测试本质上是相同的，但需要更少的整体样板和代码.

At that point though, it kind of begs the question why you're using classes instead of just defining functions, since the test will essentially be the same, but require less overall boilerplate and code.

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