@Test
public void testIsStale() {

  underTest.add(createEntry());
  underTest.currentBatch.lastRpcSentTimeNanos = time.get();
  Assert.assertFalse(underTest.currentBatch.isStale());
  time.addAndGet(BulkMutation.MAX_RPC_WAIT_TIME_NANOS);
  Assert.assertTrue(underTest.currentBatch.isStale());
}