Question

当使用python 3中的unittest库时，我只想在测试失败时做一些操作（但这应该在类级别，所以我不必为每个测试编写它）。例如，当使用 behave 时，有类似的东西：

def after_step(context, step):
    if step.status == "failed":
        ...

unittest库是否有类似内容，如果没有，那么做类似的最简单的方法是什么？

Answer 1

我最近尝试做类似的事情，我找到了出路：

import unittest

class MyTestResult(unittest.TestResult):
    def addFailure(self, test, err):
        # here you can do what you want to do when a test case fails 
        print('test failed!')
        super(MyTestResult, self).addFailure(test, err)

    def addError(self, test, err):
        # here you can do what you want to do when a test case raises an error
        super(MyTestResult, self).addError(test, err)

class MyUT(unittest.TestCase):
    def test_fail(self):
        self.assertEqual(1, 2, '123')
        self.assertTrue("ABc".isupper())

if __name__ == '__main__':
    unittest.main(testRunner=unittest.TextTestRunner(resultclass=MyTestResult))

如果你想根据不同的测试用例类做不同的工作，你可以这样做：

import unittest

class MyUT(unittest.TestCase):
    class TestResult(unittest.TestResult):
        def addFailure(self, test, err):
            print('do something when test case failed')
            super(MyUT.TestResult, self).addFailure(test, err)
        def addError(self, test, err):
            print('test case error')
            super(MyUT.TestResult, self).addError(test, err)

    def test_fail(self):
        self.assertEqual(1, 2, "1=2")

class MyUT2(unittest.TestCase):
    class TestResult(unittest.TestResult):
        def addFailure(self, test, err):
            print('do something else when test case failed')
            super(MyUT2.TestResult, self).addFailure(test, err)
        def addError(self, test, err):
            print('test case error')
            super(MyUT2.TestResult, self).addError(test, err)

    def test_fail(self):
        self.assertEqual(1, 2, "1=2")

if __name__ == '__main__':
    classes = [MyUT, MyUT2]
    for c in classes:
        suite = unittest.TestLoader().loadTestsFromTestCase(c)
        unittest.TextTestRunner(resultclass=c.TestResult).run(suite)

Answer 2

您可以尝试使用装饰器：

class ExceptionHandler(object):
def __init__(self, f):
    self.f = f

def __call__(self, *args, **kwargs):
    try:
        self.f(*args, **kwargs)
    except:
        print('do smth')

在单元测试中：

@ExceptionHandler  
def test_fail(self):
    self.assert_false(True)

Answer 3

您可以对这些很酷的东西。通过调用原始设置的自定义覆盖默认异常处理程序，并设置自定义属性：

import sys
import unittest
has_failures = []

class IntegrationTests(unittest.TestCase):
    old_failureException = unittest.TestCase.failureException

    @property
    def failureException(self):
        has_failures.append('fail')
        return self.old_failureException

    def setUp(self):
        sys.stderr.write('Setup for %s\n' % self._testMethodName)

        if has_failures:
            self.skipTest("An test has failed, skipping everything else!")

    def test_thing1(self):
        self.assertEqual(1, 2)

    def test_thing2(self):
        pass

def load_tests(loader, standard_tests, pattern):
    suite = unittest.TestSuite()
    suite.addTest( IntegrationTests( 'test_thing1' ) )
    suite.addTest( IntegrationTests( 'test_thing2' ) )
    return suite

# Comment this to run individual Unit Tests
load_tests = None

if __name__ == "__main__":
    unittest.main(verbosity=3)

结果：

test_thing1 (__main__.IntegrationTests) ... Setup for test_thing1
FAIL
test_thing2 (__main__.IntegrationTests) ... Setup for test_thing2
skipped 'An test has failed, skipping everything else!'

======================================================================
FAIL: test_thing1 (__main__.IntegrationTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\User\Downloads\text.py", line 27, in test_thing1
    self.assertEqual(1, 2)
AssertionError: 1 != 2

----------------------------------------------------------------------
Ran 2 tests in 0.003s

FAILED (failures=1, skipped=1)

参考文献：

Answer 4

使用私有变量不是很好，但我还没有找到其他方法来访问跟踪测试结果的对象。

import unittest

class TmpTest(unittest.TestCase):

    def tearDown(self):
        result = self._resultForDoCleanups
        if not result.wasSuccessful():
            print "*** test failed"

    def testFoo(self):
        self.assertEqual(2, 2)

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

Python unittest，仅在测试失败时执行某些操作

4 个答案: