@SuppressWarnings("unchecked")
@Test
public void testExecutorProblem() throws Exception {

  ExecutorService mockExecutor = Mockito.mock(ExecutorService.class);
  when(mockExecutor.submit(any(Callable.class))).thenThrow(new RuntimeException(""));
  underTest = new OAuthCredentialsCache(mockExecutor, mockCredentials);
  Assert.assertFalse(underTest.getHeader(TIMEOUT_SECONDS, TimeUnit.SECONDS).getStatus().isOk());
}