我有一些测试数据,想为每个项目创建一个单元测试。我的第一个想法是这样做的:

import unittest

l = [["foo", "a", "a",], ["bar", "a", "b"], ["lee", "b", "b"]]

class TestSequence(unittest.TestCase):
    def testsample(self):
        for name, a,b in l:
            print "test", name
            self.assertEqual(a,b)

if __name__ == '__main__':
    unittest.main()

这样做的缺点是它在一个测试中处理所有数据。我想在飞行中为每个项目生成一个测试。有什么建议吗?


当前回答

从Python 3.4开始,已经为此目的向unittest引入了子测试。详细信息请参见文档。TestCase。subTest是一个上下文管理器,它允许在测试中隔离断言,以便用参数信息报告失败,但它不会停止测试执行。下面是文档中的例子:

class NumbersTest(unittest.TestCase):

def test_even(self):
    """
    Test that numbers between 0 and 5 are all even.
    """
    for i in range(0, 6):
        with self.subTest(i=i):
            self.assertEqual(i % 2, 0)

测试运行的输出是:

======================================================================
FAIL: test_even (__main__.NumbersTest) (i=1)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 32, in test_even
    self.assertEqual(i % 2, 0)
AssertionError: 1 != 0

======================================================================
FAIL: test_even (__main__.NumbersTest) (i=3)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 32, in test_even
    self.assertEqual(i % 2, 0)
AssertionError: 1 != 0

======================================================================
FAIL: test_even (__main__.NumbersTest) (i=5)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "subtests.py", line 32, in test_even
    self.assertEqual(i % 2, 0)
AssertionError: 1 != 0

这也是unittest2的一部分,因此可用于早期版本的Python。

其他回答

这可以使用元类优雅地解决:

import unittest

l = [["foo", "a", "a",], ["bar", "a", "b"], ["lee", "b", "b"]]

class TestSequenceMeta(type):
    def __new__(mcs, name, bases, dict):

        def gen_test(a, b):
            def test(self):
                self.assertEqual(a, b)
            return test

        for tname, a, b in l:
            test_name = "test_%s" % tname
            dict[test_name] = gen_test(a,b)
        return type.__new__(mcs, name, bases, dict)

class TestSequence(unittest.TestCase):
    __metaclass__ = TestSequenceMeta

if __name__ == '__main__':
    unittest.main()

这实际上与之前的回答中提到的parameterized相同,但具体到unittest:

def sub_test(param_list):
    """Decorates a test case to run it as a set of subtests."""

    def decorator(f):

        @functools.wraps(f)
        def wrapped(self):
            for param in param_list:
                with self.subTest(**param):
                    f(self, **param)

        return wrapped

    return decorator

使用示例:

class TestStuff(unittest.TestCase):
    @sub_test([
        dict(arg1='a', arg2='b'),
        dict(arg1='x', arg2='y'),
    ])
    def test_stuff(self, arg1, arg2):
        ...

您可以使用TestSuite和自定义TestCase类。

import unittest

class CustomTest(unittest.TestCase):
    def __init__(self, name, a, b):
        super().__init__()
        self.name = name
        self.a = a
        self.b = b

    def runTest(self):
        print("test", self.name)
        self.assertEqual(self.a, self.b)

if __name__ == '__main__':
    suite = unittest.TestSuite()
    suite.addTest(CustomTest("Foo", 1337, 1337))
    suite.addTest(CustomTest("Bar", 0xDEAD, 0xC0DE))
    unittest.TextTestRunner().run(suite)

我有麻烦使这些工作为setUpClass。

下面是Javier回答的一个版本,它允许setUpClass访问动态分配的属性。

import unittest


class GeneralTestCase(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        print ''
        print cls.p1
        print cls.p2

    def runTest1(self):
        self.assertTrue((self.p2 - self.p1) == 1)

    def runTest2(self):
        self.assertFalse((self.p2 - self.p1) == 2)


def load_tests(loader, tests, pattern):
    test_cases = unittest.TestSuite()
    for p1, p2 in [(1, 2), (3, 4)]:
        clsname = 'TestCase_{}_{}'.format(p1, p2)
        dct = {
            'p1': p1,
            'p2': p2,
        }
        cls = type(clsname, (GeneralTestCase,), dct)
        test_cases.addTest(cls('runTest1'))
        test_cases.addTest(cls('runTest2'))
    return test_cases

输出

1
2
..
3
4
..
----------------------------------------------------------------------
Ran 4 tests in 0.000s

OK

这可以通过使用pytest来完成。只需要编写test_me.py文件的内容:

import pytest

@pytest.mark.parametrize('name, left, right', [['foo', 'a', 'a'],
                                               ['bar', 'a', 'b'],
                                               ['baz', 'b', 'b']])
def test_me(name, left, right):
    assert left == right, name

并使用py命令运行测试。Test——tb=短test_me.py。然后输出如下所示:

=========================== test session starts ============================
platform darwin -- Python 2.7.6 -- py-1.4.23 -- pytest-2.6.1
collected 3 items

test_me.py .F.

================================= FAILURES =================================
_____________________________ test_me[bar-a-b] _____________________________
test_me.py:8: in test_me
    assert left == right, name
E   AssertionError: bar
==================== 1 failed, 2 passed in 0.01 seconds ====================

这很简单!此外,pytest还有更多的功能,如fixture、标记、断言等。