如何避免在测试用例失败后执行 Python UnitTest 方法“addCleanup”？答案

【问题标题】：How to avoid execution of Python UnitTest method "addCleanup" after test case failure?如何避免在测试用例失败后执行 Python UnitTest 方法“addCleanup”？
【发布时间】：2019-01-24 12:51:47
【问题描述】：

我有以下 Python 单元测试：

import unittest

class SimpleTestCases(unittest.TestCase):
    def setUp(self):
        print "\nmessage from function: setUp"
        self.createResource()
        self.addCleanup(self.cleanResource)

    def createResource(self):
        print "\nmessage from function: createResource"

    def cleanResource(self):
        print "\nmessage from function: cleanResource"

    def test_func1(self):
        print "message from function: test_func1::start"
        print "message from function: test_func1::end"

    def test_func2(self):
        print "message from function: test_func2::start"

        self.assertTrue(False)

        print "message from function: test_func2::end"

    def test_func3(self):
        print "message from function: test_func3::start"
        print "message from function: test_func3:end"

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

在上面的代码执行后，带有选项“-f”的函数按以下顺序执行

python -m unittest -fb test_cases

message from function: setUp

message from function: createResource
message from function: test_func1::start
message from function: test_func1::end

message from function: cleanResource
.
message from function: setUp

message from function: createResource
message from function: test_func2::start
F
message from function: cleanResource

======================================================================
FAIL: test_func2 (test_cases.SimpleTestCases)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "test_cases.py", line 23, in test_func2
    self.assertTrue(False)
AssertionError: False is not true

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)

它会在第一次失败后停止执行，但会调用 "addCleanup" 方法。

我想避免在测试函数"test_func2"时调用"addCleanup"方法，这样创建的资源就可以用于调试目的了。

是否有可用的命令行选项或解决方法？

【问题讨论】：

AFAIK doCleanup 无论如何都会运行。您可以在测试中设置一些实例变量，然后在清理函数中检查它的值。不漂亮，但可能有用

标签： python unit-testing python-unittest

【解决方案1】：

作为最简单的方法之一 - 只是将输入（Python 2 的 raw_input）放在 cleanResource 方法的开头。所以执行将停止，直到按下 Enter 键。

def cleanResource(self):
    temp = raw_input('wait before cleanResource')
    print("\nmessage from function: cleanResource")

另一种方法是在调试器中使用断点

import pdb

然后

pdb.set_trace()

需要的地方

【讨论】：

是的，它可能被用作一次性异常，只是为了调试特定的问题......当然不用于工作代码。

【解决方案2】：

根据单元测试文档，doCleanups() 是负责调用所有清理方法的方法。

一种方法是在 doCleanups 方法中检查测试用例的结果，如果测试用例失败则弹出所有清理方法并跳过其余测试用例

下面是代码：

import unittest

class SimpleTestCases(unittest.TestCase):
    FAILURE = False

    def setUp(self):
        print "\nmessage from function: setUp"
        if SimpleTestCases.FAILURE:
            self.skipTest("Test is skipped due to first failure")

            return super(SimpleTestCases, self).setUp()

        self.createResource()
        self.addCleanup(self.cleanResource)

    def createResource(self):
        msg = "\nmessage from function: createResource"

    def cleanResource(self):
        print "\nmessage from function: cleanResource"

    def test_func1(self):
        print "message from function: test_func1::start"
        print "message from function: test_func1::end"

    def test_func2(self):
        print "message from function: test_func2::start"

        self.assertTrue(False)

        print "message from function: test_func2::end"

    def test_func3(self):
        print "message from function: test_func3::start"
        print "message from function: test_func3:end"

    def doCleanups(self):
        print "message from function: doCleanups"
        if SimpleTestCases.FAILURE:
            return super(SimpleTestCases, self).doCleanups()

        result = getattr(self, '_outcomeForDoCleanups', self._resultForDoCleanups)

        ok_result = True
        exc_list = getattr(result, 'failures')

        if exc_list and exc_list[-1][0] is self:
            ok_result = ok_result and not exc_list[-1][1]

        if not ok_result:
            SimpleTestCases.FAILURE = True
            while self._cleanups:
                (func, args, kwargs) = self._cleanups.pop()

        return super(SimpleTestCases, self).doCleanups()

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

执行为

python -m unittest test_cases

然后输出：

message from function: setUp
message from function: test_func1::start
message from function: test_func1::end
message from function: doCleanups

message from function: cleanResource
.
message from function: setUp
message from function: test_func2::start
Fmessage from function: doCleanups

message from function: setUp
smessage from function: doCleanups

======================================================================
FAIL: test_func2 (test_cases.SimpleTestCases)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "test_cases.py", line 30, in test_func2
    self.assertTrue(False)
AssertionError: False is not true

----------------------------------------------------------------------
Ran 3 tests in 0.000s

FAILED (failures=1, skipped=1)

【讨论】：