Container containerHost1 = createContainer(1, host1[0], resource, priority);
Container containerHost2 = createContainer(2, host2[0], resource, priority);
drainNotifier.set(false);
taskScheduler.onContainersAllocated(Lists.newArrayList(containerHost1, containerHost2));
TestTaskSchedulerHelpers.waitForDelayedDrainNotify(drainNotifier);
drainableAppCallback.drain();
verify(taskSchedulerEventHandler).taskAllocated(eq(ta11), any(Object.class), eq(containerHost1));
verify(taskSchedulerEventHandler).taskAllocated(eq(ta21), any(Object.class), eq(containerHost2));