@Test
public void testVerifyToken() throws Exception {

      when(verifier.verify(TOKEN))
      .thenReturn(token)
      .thenThrow(new GeneralSecurityException())
      .thenThrow(new IOException())
      .thenThrow(new IllegalArgumentException());
  assertEquals(token, authenticator.verifyToken(TOKEN));
  for (int i = 0; i < 3; i++) {
    assertNull(authenticator.verifyToken(TOKEN));
  }
}