### Question:
RingGroupUpdateTransitionFunctionImpl implements RingGroupTransitionFunction { protected boolean isFullyServing(Host host, boolean isObserved) throws IOException { return PartitionUtils.isFullyServing(host, isObserved, status); } RingGroupUpdateTransitionFunctionImpl(PartitionAssigner partitionAssigner,
                                               HostReplicaStatus status); @Override void manageTransitions(Coordinator coordinator, RingGroup ringGroup);  }### Answer:
@Test public void testIsFullyServing() throws IOException { RingGroupUpdateTransitionFunctionImpl transitionFunction = new RingGroupUpdateTransitionFunctionImpl( null, new HostReplicaStatus(1, 2, 0, 0, 0, null) ); setUpRing(r0, v1, v1, HostState.IDLE); assertFalse(transitionFunction.isFullyServing(r0h0, true)); assertFalse(transitionFunction.isFullyServing(r0h1, true)); r0h0.setState(HostState.SERVING); assertFalse(transitionFunction.isFullyServing(r0h0, true)); assertFalse(transitionFunction.isFullyServing(r0h1, true)); r0h1.setState(HostState.SERVING); assertTrue(transitionFunction.isFullyServing(r0h0, true)); assertFalse(transitionFunction.isFullyServing(r0h1, true)); assertTrue(transitionFunction.isFullyServing(r0h1, true)); r0h0.enqueueCommand(HostCommand.GO_TO_IDLE); assertFalse(transitionFunction.isFullyServing(r0h0, true)); r0h0.setCurrentCommand(HostCommand.GO_TO_IDLE); r0h0.clearCommandQueue(); assertFalse(transitionFunction.isFullyServing(r0h0, true)); }