def test_umask(self):
        with AlternateReactor(FakeDaemonizingReactor()):
            self.runner.setupEnvironment(None, ".", False, 123, None)
        self.assertEqual(self.mask, 123)
L{UnixApplicationRunner.setupEnvironment} changes the process umask to
dataset/ETHPy150Open twisted/twisted/twisted/test/test_twistd.py/UnixApplicationRunnerSetupEnvironmentTests.test_umask