Skip testcase unless it's explicitly called in the arguments

I want to skip tests unless they are explicitly listed in the command line arguments. This is needed to skip stresstests:

class StressTest(unittest.TestCase):
    @skipSomehow...
    def test_time(self):
        ...

Currently, I'm doing unittest.skipUnless('StressTest' in sys.argv, ...). However, this is not flexible (what if someone run it with StressTest.test_time argument?)

Are there better ways to do it?