### Question:
AbstractRebalancer implements Rebalancer<T>,
    MappingCalculator<T> { protected Map<String, String> computeBestPossibleStateForPartition(Set<String> liveInstances, StateModelDefinition stateModelDef, List<String> preferenceList, CurrentStateOutput currentStateOutput, Set<String> disabledInstancesForPartition, IdealState idealState, ClusterConfig clusterConfig, Partition partition, MonitoredAbnormalResolver monitoredResolver) { Optional<Map<String, String>> optionalOverwrittenStates = computeStatesOverwriteForPartition(stateModelDef, preferenceList, currentStateOutput, idealState, partition, monitoredResolver); if (optionalOverwrittenStates.isPresent()) { return optionalOverwrittenStates.get(); } Map<String, String> currentStateMap = new HashMap<>( currentStateOutput.getCurrentStateMap(idealState.getResourceName(), partition)); return computeBestPossibleMap(preferenceList, stateModelDef, currentStateMap, liveInstances, disabledInstancesForPartition); }  @Override void init(HelixManager manager); @Override abstract IdealState computeNewIdealState(
      String resourceName, IdealState currentIdealState, CurrentStateOutput currentStateOutput,
      T clusterData); @Override ResourceAssignment computeBestPossiblePartitionState(
      T cache, IdealState idealState, Resource resource,
      CurrentStateOutput currentStateOutput); static List<String> getPreferenceList(Partition partition, IdealState idealState,
      Set<String> eligibleInstances); static int getStateCount(String state, StateModelDefinition stateModelDef, int liveAndEnabledSize,
      int preferenceListSize);  }### Answer:
@Test(dataProvider = "TestComputeBestPossibleStateInput") public void testComputeBestPossibleState(String comment, String stateModelName, List<String> liveInstances, List<String> preferenceList, Map<String, String> currentStateMap, List<String> disabledInstancesForPartition, Map<String, String> expectedBestPossibleMap) { System.out.println("Test case comment: " + comment); AutoRebalancer rebalancer = new AutoRebalancer(); Partition partition = new Partition("testPartition"); CurrentStateOutput currentStateOutput = new CurrentStateOutput(); for (String instance : currentStateMap.keySet()) { currentStateOutput .setCurrentState("test", partition, instance, currentStateMap.get(instance)); } Map<String, String> bestPossibleMap = rebalancer .computeBestPossibleStateForPartition(new HashSet<>(liveInstances), BuiltInStateModelDefinitions.valueOf(stateModelName).getStateModelDefinition(), preferenceList, currentStateOutput, new HashSet<>(disabledInstancesForPartition), new IdealState("test"), new ClusterConfig("TestCluster"), partition, MonitoredAbnormalResolver.DUMMY_STATE_RESOLVER); Assert.assertTrue(bestPossibleMap.equals(expectedBestPossibleMap)); }