def METHOD_NAME(self):
    with self.assertRaises(ValueError):
        userNameToFileName(b"a")
    with self.assertRaises(ValueError):
        userNameToFileName({"a"})
    with self.assertRaises(ValueError):
        userNameToFileName(("a",))
    with self.assertRaises(ValueError):
        userNameToFileName(["a"])
    with self.assertRaises(ValueError):
        userNameToFileName(["a"])
    with self.assertRaises(ValueError):
        userNameToFileName(b"\xd8\x00")