### Question:
CopybookRepositoryLRU implements CopybookRepository { @Override public String logContent() { return cache.asMap().toString(); } @Inject  CopybookRepositoryLRU(
      @Named("CACHE-MAX-SIZE") int cacheSize,
      @Named("CACHE-DURATION") int duration,
      @Named("CACHE-TIME-UNIT") String timeUnitName);   CopybookRepositoryLRU(int cacheSize, int duration, String timeUnitName, Ticker ticker); @Override Optional<CopybookModel> getCopybookStorableFromCache(@NonNull String name); @Override synchronized void persist(@NonNull CopybookModel copybookModel); @Override String logContent(); @Override int size(); @Override boolean isStored(@NonNull String name); @Override void invalidateCache();  }### Answer:
@Test void testLogCacheContent() { assertNotNull(repository.logContent()); }