'When the file auth plugin is given a file that doesn\'t exist, it
should produce a warning.'

def test_warnWithBadFilename(self):

    oldOutput = cred_file.theFileCheckerFactory.errorOutput
    newOutput = StringIO()
    cred_file.theFileCheckerFactory.errorOutput = newOutput
    strcred.makeChecker(('file:' + self._fakeFilename()))
    cred_file.theFileCheckerFactory.errorOutput = oldOutput
    self.assertIn(cred_file.invalidFileWarning, newOutput.getvalue())
