PyUnit: stop after first failing test?

Question

I'm using the following code in my testing framework:

testModules = ["test_foo", "test_bar"]

suite = unittest.TestLoader().loadTestsFromNames(testModules)
runner = unittest.TextTestRunner(sys.stdout, verbosity=2)
results = runner.run(suite)
return results.wasSuccessful()

Is there a way to make the reporting (runner.run?) abort after the first failure to prevent excessive verbosity?

Answer 1

Nine years after the question was asked, this is still one of the top search results for "python unit test fail early" and, as I discovered when looking at the other search results, these answers are no longer correct for more recent versions of the unittest module.

The documentation for the unittest module https://docs.python.org/3/library/unittest.html#command-line-options and https://docs.python.org/2.7/library/unittest.html#command-line-options show that there is an argument, failfast=True, that can be added to unittest.main, or equivalently a command line option, -f, or --failfast, to stop the test run on the first error or failure. This option was added in version 2.7. Using that option is a lot easier than the previously-necessary workarounds suggested in the other answers.

That is, simply change your

unittest.main()

to

unittest.main(failfast=True)

Answer 2

It's a feature. If you want to override this, you'll need to subclass TestCase and/or TestSuite classes and override logic in the run() method.

P.S.: I think you have to subclass unittest.TestCase and override method run() in your class:

def run(self, result=None):
    if result is None: result = self.defaultTestResult()
    result.startTest(self)
    testMethod = getattr(self, self._testMethodName)
    try:
        try:
            self.setUp()
        except KeyboardInterrupt:
            raise
        except:
            result.addError(self, self._exc_info())
            return

        ok = False
        try:
            testMethod()
            ok = True
        except self.failureException:
            result.addFailure(self, self._exc_info())
            result.stop()
        except KeyboardInterrupt:
            raise
        except:
            result.addError(self, self._exc_info())
            result.stop()

        try:
            self.tearDown()
        except KeyboardInterrupt:
            raise
        except:
            result.addError(self, self._exc_info())
            ok = False
        if ok: result.addSuccess(self)
    finally:
        result.stopTest(self)

(I've added two result.stop() calls to the default run definition).

Then you'll have to modify all your testcases to make them subclasses of this new class, instead of unittest.TestCase.

WARNING: I didn't test this code. :)