def test_basic(self):
from pyanaconda.bootloader import Arguments
a = Arguments()
a.update(set(["a", "b", "c"]))
b = Arguments()
b.add("b")
diff = a - b
self.assertEqual(diff, set(["a", "c"]))
self.assertIsInstance(diff, Arguments)
assert(str(diff) in ["a c", "c a"])
