### Question:
ContainerDBServiceProviderImpl implements ContainerDBServiceProvider { @Override public void incrementContainerCountBy(long count) { long containersCount = getCountForContainers(); storeContainerCount(containersCount + count); } @Inject  ContainerDBServiceProviderImpl(DBStore dbStore,
                                        Configuration sqlConfiguration); @Override void close(); @Override void initNewContainerDB(Map<ContainerKeyPrefix, Integer>
                                     containerKeyPrefixCounts); @Override void storeContainerKeyMapping(ContainerKeyPrefix containerKeyPrefix,
                                       Integer count); @Override void storeContainerKeyCount(Long containerID, Long count); @Override long getKeyCountForContainer(Long containerID); @Override boolean doesContainerExists(Long containerID); @Override Integer getCountForContainerKeyPrefix(
      ContainerKeyPrefix containerKeyPrefix); @Override Map<ContainerKeyPrefix, Integer> getKeyPrefixesForContainer(
      long containerId); @Override Map<ContainerKeyPrefix, Integer> getKeyPrefixesForContainer(
      long containerId, String prevKeyPrefix); @Override Map<Long, ContainerMetadata> getContainers(int limit,
                                                    long prevContainer); @Override void deleteContainerMapping(ContainerKeyPrefix containerKeyPrefix); @Override long getCountForContainers(); @Override TableIterator getContainerTableIterator(); @Override void storeContainerCount(Long count); @Override void incrementContainerCountBy(long count);  }### Answer:
@Test public void testIncrementContainerCountBy() throws Exception { assertEquals(0, containerDbServiceProvider.getCountForContainers()); containerDbServiceProvider.incrementContainerCountBy(1L); assertEquals(1L, containerDbServiceProvider.getCountForContainers()); containerDbServiceProvider.incrementContainerCountBy(3L); assertEquals(4L, containerDbServiceProvider.getCountForContainers()); }