@Test(timeout = 60000)
public void testFifoScheduling() throws Exception {

  GenericTestUtils.setRootLogLevel(Level.DEBUG);
  MockRM rm = new MockRM(conf);
  rm.start();
  MockNM nm1 = rm.registerNode("127.0.0.1:1234", 6 * GB);
  MockNM nm2 = rm.registerNode("127.0.0.2:5678", 4 * GB);
  RMApp app1 = MockRMAppSubmitter.submitWithMemory(2048, rm);
  // kick the scheduling, 2 GB given to AM1, remaining 4GB on nm1
  nm1.nodeHeartbeat(true);
  RMAppAttempt attempt1 = app1.getCurrentAppAttempt();
  MockAM am1 = rm.sendAMLaunched(attempt1.getAppAttemptId());
  am1.registerAppAttempt();
  SchedulerNodeReport report_nm1 =
      rm.getResourceScheduler().getNodeReport(nm1.getNodeId());
  Assert.assertEquals(2 * GB, report_nm1.getUsedResource().getMemorySize());
  RMApp app2 = MockRMAppSubmitter.submitWithMemory(2048, rm);
  // kick the scheduling, 2GB given to AM, remaining 2 GB on nm2
  nm2.nodeHeartbeat(true);
  RMAppAttempt attempt2 = app2.getCurrentAppAttempt();
  MockAM am2 = rm.sendAMLaunched(attempt2.getAppAttemptId());
  am2.registerAppAttempt();
  SchedulerNodeReport report_nm2 =
      rm.getResourceScheduler().getNodeReport(nm2.getNodeId());
  Assert.assertEquals(2 * GB, report_nm2.getUsedResource().getMemorySize());
  // add request for containers
  am1.addRequests(new String[] { "127.0.0.1", "127.0.0.2" }, GB, 1, 1);
  AllocateResponse alloc1Response = am1.schedule(); // send the request
  // add request for containers
  am2.addRequests(new String[] { "127.0.0.1", "127.0.0.2" }, 3 * GB, 0, 1);
  AllocateResponse alloc2Response = am2.schedule(); // send the request
  // kick the scheduler, 1 GB and 3 GB given to AM1 and AM2, remaining 0
  nm1.nodeHeartbeat(true);
  while (alloc1Response.getAllocatedContainers().size() < 1) {
    LOG.info("Waiting for containers to be created for app 1...");
    Thread.sleep(1000);
    alloc1Response = am1.schedule();
  }
  while (alloc2Response.getAllocatedContainers().size() < 1) {
    LOG.info("Waiting for containers to be created for app 2...");
    Thread.sleep(1000);
    alloc2Response = am2.schedule();
  }
  // kick the scheduler, nothing given remaining 2 GB.
  nm2.nodeHeartbeat(true);
  List<Container> allocated1 = alloc1Response.getAllocatedContainers();
  Assert.assertEquals(1, allocated1.size());
  Assert.assertEquals(1 * GB, allocated1.get(0).getResource().getMemorySize());
  Assert.assertEquals(nm1.getNodeId(), allocated1.get(0).getNodeId());
  List<Container> allocated2 = alloc2Response.getAllocatedContainers();
  Assert.assertEquals(1, allocated2.size());
  Assert.assertEquals(3 * GB, allocated2.get(0).getResource().getMemorySize());
  Assert.assertEquals(nm1.getNodeId(), allocated2.get(0).getNodeId());
  report_nm1 = rm.getResourceScheduler().getNodeReport(nm1.getNodeId());
  report_nm2 = rm.getResourceScheduler().getNodeReport(nm2.getNodeId());
  Assert.assertEquals(0, report_nm1.getAvailableResource().getMemorySize());
  Assert.assertEquals(2 * GB, report_nm2.getAvailableResource().getMemorySize());
  Assert.assertEquals(6 * GB, report_nm1.getUsedResource().getMemorySize());
  Assert.assertEquals(2 * GB, report_nm2.getUsedResource().getMemorySize());
  Container c1 = allocated1.get(0);
  Assert.assertEquals(GB, c1.getResource().getMemorySize());
  ContainerStatus containerStatus =
      BuilderUtils.newContainerStatus(c1.getId(), ContainerState.COMPLETE,
          "", 0, c1.getResource());
  nm1.containerStatus(containerStatus);
  int waitCount = 0;
  while (attempt1.getJustFinishedContainers().size() < 1 && waitCount++ != 20) {
    LOG.info("Waiting for containers to be finished for app 1... Tried "
        + waitCount + " times already..");
    Thread.sleep(1000);
  }
  Assert.assertEquals(1, attempt1.getJustFinishedContainers().size());
  Assert.assertEquals(1, am1.schedule().getCompletedContainersStatuses()
      .size());
  report_nm1 = rm.getResourceScheduler().getNodeReport(nm1.getNodeId());
  Assert.assertEquals(5 * GB, report_nm1.getUsedResource().getMemorySize());
  rm.stop();
}