'Check that --testmodule does *not* support module names as arguments
and that it displays a meaningful error message.'

def test_testmoduleOnModuleName(self):

    buffy = NativeStringIO()
    (stderr, sys.stderr) = (sys.stderr, buffy)
    moduleName = 'twisted.trial.test.test_script'
    try:
        self.config.opt_testmodule(moduleName)
        self.assertEqual(0, len(self.config['tests']))
        self.assertEqual(("File    %r    doesn't    exist\n" % (moduleName,)), buffy.getvalue())
    finally:
        sys.stderr = stderr
