def METHOD_NAME(self):
    # flags.discard_new=False --> no discard
    fmt = LUKS(exists=False)
    self.assertEqual(fmt.options, None)
    fmt = LUKS(exists=True)
    self.assertEqual(fmt.options, None)
    # flags.discard_new=True --> discard if creating new
    with patch("blivet.flags.flags.discard_new", True):
        fmt = LUKS(exists=True)
        self.assertEqual(fmt.options, None)
        fmt = LUKS(exists=False)
        self.assertEqual(fmt.options, "discard")
        # do not add if already there
        fmt = LUKS(exists=False, options="discard")
        self.assertEqual(fmt.options, "discard")
        # add with comma after other option(s)
        fmt = LUKS(exists=False, options="blah")
        self.assertEqual(fmt.options, "blah,discard")