import org.apache.hadoop.ha.TestNodeFencer.AlwaysFailFencer; //导入依赖的package包/类
@Test
public void testFailoverFromFaultyServiceFencingFailure() throws Exception {
  DummyHAService svc1 = new DummyHAService(HAServiceState.ACTIVE, svc1Addr);
  Mockito.doThrow(new ServiceFailedException("Failed!"))
      .when(svc1.proxy).transitionToStandby(anyReqInfo());

  DummyHAService svc2 = new DummyHAService(HAServiceState.STANDBY, svc2Addr);
  svc1.fencer = svc2.fencer = setupFencer(AlwaysFailFencer.class.getName());

  AlwaysFailFencer.fenceCalled = 0;
  try {
    doFailover(svc1, svc2, false, false);
    fail("Failed over even though fencing failed");
  } catch (FailoverFailedException ffe) {
    // Expected
  }

  assertEquals(1, AlwaysFailFencer.fenceCalled);
  assertSame(svc1, AlwaysFailFencer.fencedSvc);
  assertEquals(HAServiceState.ACTIVE, svc1.state);
  assertEquals(HAServiceState.STANDBY, svc2.state);
}
 

import org.apache.hadoop.ha.TestNodeFencer.AlwaysFailFencer; //导入依赖的package包/类
@Test
public void testFencingFailureDuringFailover() throws Exception {
  DummyHAService svc1 = new DummyHAService(HAServiceState.ACTIVE, svc1Addr);
  DummyHAService svc2 = new DummyHAService(HAServiceState.STANDBY, svc2Addr);
  svc1.fencer = svc2.fencer = setupFencer(AlwaysFailFencer.class.getName());

  AlwaysFailFencer.fenceCalled = 0;
  try {
    doFailover(svc1, svc2, true, false);
    fail("Failed over even though fencing requested and failed");
  } catch (FailoverFailedException ffe) {
    // Expected
  }

  // If fencing was requested and it failed we don't try to make
  // svc2 active anyway, and we don't failback to svc1.
  assertEquals(1, AlwaysFailFencer.fenceCalled);
  assertSame(svc1, AlwaysFailFencer.fencedSvc);
  assertEquals(HAServiceState.STANDBY, svc1.state);
  assertEquals(HAServiceState.STANDBY, svc2.state);
}
 

import org.apache.hadoop.ha.TestNodeFencer.AlwaysFailFencer; //导入依赖的package包/类
@Test
public void testFailureToFenceOnFailbackFailsTheFailback() throws Exception {
  DummyHAService svc1 = new DummyHAService(HAServiceState.ACTIVE, svc1Addr);
  DummyHAService svc2 = new DummyHAService(HAServiceState.STANDBY, svc2Addr);
  Mockito.doThrow(new IOException("Failed!"))
      .when(svc2.proxy).transitionToActive(anyReqInfo());
  svc1.fencer = svc2.fencer = setupFencer(AlwaysFailFencer.class.getName());
  AlwaysFailFencer.fenceCalled = 0;

  try {
    doFailover(svc1, svc2, false, false);
    fail("Failed over to service that won't transition to active");
  } catch (FailoverFailedException ffe) {
    // Expected
  }

  // We did not fence svc1 because it cooperated and we didn't force it, 
  // we failed to failover so we fenced svc2, we failed to fence svc2
  // so we did not failback to svc1, ie it's still standby.
  assertEquals(HAServiceState.STANDBY, svc1.state);
  assertEquals(1, AlwaysFailFencer.fenceCalled);
  assertSame(svc2, AlwaysFailFencer.fencedSvc);
}