Mockito.eq(NameNodeFile.IMAGE), Mockito.any(Canceler.class));
// Perform some edits and wait for a checkpoint to start on the SBN.
doEdits(0, 1000);
nn0.getRpcServer().rollEditLog();
answerer.waitForCall();
assertTrue("SBN is not performing checkpoint but it should be.",
answerer.getFireCount() == 1 && answerer.getResultCount() == 0);
// Make sure that the lock has actually been taken by the checkpointing
// thread.