def test_euid(self):
        util.switchUID(12000, None, True)
        self.assertEqual(self.initgroupsCalls, [(12000, None)])
        self.assertEqual(self.mockos.seteuidCalls, [12000])
L{util.switchUID} calls L{util.initgroups} and then C{os.seteuid} with
dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/python/test/test_util.py/SwitchUIDTest.test_euid