// no preemption - container assignment attempts < 3
scheduler.getProgress();
drainableAppCallback.drain();
verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId)any());
heldContainer.incrementAssignmentAttempts();
heldContainer.incrementAssignmentAttempts();
// preemption - container released and resource asked again
scheduler.getProgress();
drainableAppCallback.drain();
verify(mockRMClient, times(1)).releaseAssignedContainer((ContainerId)any());
verify(mockRMClient, times(1)).releaseAssignedContainer(mockCId4);