/** @throws Exception If failed. */
  public void testSystemCache() throws Exception {
    CollectionConfiguration colCfg = collectionConfiguration();

    IgniteQueue queue = grid(0).queue("Queue1", 0, colCfg);

    final CacheConfiguration ccfg = getQueueCache(queue);

    GridTestUtils.assertThrows(
        log,
        new Callable<Object>() {
          @Override
          public Object call() throws Exception {
            grid(0).cache(ccfg.getName());
            return null;
          }
        },
        IllegalStateException.class,
        "Failed to get cache because it is a system cache");

    assertNotNull(((IgniteKernal) grid(0)).internalCache(ccfg.getName()));
  }
  /**
   * @param name Cache name.
   * @param cacheMode Cache mode.
   * @param parts Number of partitions.
   * @return Cache configuration.
   */
  private CacheConfiguration cacheConfiguration(String name, CacheMode cacheMode, int parts) {
    CacheConfiguration ccfg = new CacheConfiguration();

    ccfg.setName(name);
    ccfg.setCacheMode(cacheMode);
    ccfg.setAtomicityMode(TRANSACTIONAL);
    ccfg.setWriteSynchronizationMode(FULL_SYNC);

    if (cacheMode == PARTITIONED) ccfg.setBackups(1);

    ccfg.setAffinity(new RendezvousAffinityFunction(false, parts));

    return ccfg;
  }
  /**
   * Start grid with IGFS.
   *
   * @param gridName Grid name.
   * @param igfsName IGFS name
   * @param mode IGFS mode.
   * @param secondaryFs Secondary file system (optional).
   * @param restCfg Rest configuration string (optional).
   * @return Started grid instance.
   * @throws Exception If failed.
   */
  protected Ignite startGridWithIgfs(
      String gridName,
      String igfsName,
      IgfsMode mode,
      @Nullable IgfsSecondaryFileSystem secondaryFs,
      @Nullable IgfsIpcEndpointConfiguration restCfg)
      throws Exception {
    FileSystemConfiguration igfsCfg = new FileSystemConfiguration();

    igfsCfg.setDataCacheName("dataCache");
    igfsCfg.setMetaCacheName("metaCache");
    igfsCfg.setName(igfsName);
    igfsCfg.setBlockSize(IGFS_BLOCK_SIZE);
    igfsCfg.setDefaultMode(mode);
    igfsCfg.setIpcEndpointConfiguration(restCfg);
    igfsCfg.setSecondaryFileSystem(secondaryFs);
    igfsCfg.setPrefetchBlocks(PREFETCH_BLOCKS);
    igfsCfg.setSequentialReadsBeforePrefetch(SEQ_READS_BEFORE_PREFETCH);

    CacheConfiguration dataCacheCfg = defaultCacheConfiguration();

    dataCacheCfg.setName("dataCache");
    dataCacheCfg.setCacheMode(PARTITIONED);
    dataCacheCfg.setNearConfiguration(null);
    dataCacheCfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC);
    dataCacheCfg.setAffinityMapper(new IgfsGroupDataBlocksKeyMapper(2));
    dataCacheCfg.setBackups(0);
    dataCacheCfg.setAtomicityMode(TRANSACTIONAL);
    dataCacheCfg.setOffHeapMaxMemory(0);

    CacheConfiguration metaCacheCfg = defaultCacheConfiguration();

    metaCacheCfg.setName("metaCache");
    metaCacheCfg.setCacheMode(REPLICATED);
    metaCacheCfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC);
    metaCacheCfg.setAtomicityMode(TRANSACTIONAL);

    IgniteConfiguration cfg = new IgniteConfiguration();

    cfg.setGridName(gridName);

    TcpDiscoverySpi discoSpi = new TcpDiscoverySpi();

    discoSpi.setIpFinder(new TcpDiscoveryVmIpFinder(true));

    cfg.setDiscoverySpi(discoSpi);
    cfg.setCacheConfiguration(dataCacheCfg, metaCacheCfg);
    cfg.setFileSystemConfiguration(igfsCfg);

    cfg.setLocalHost("127.0.0.1");
    cfg.setConnectorConfiguration(null);

    return G.start(cfg);
  }