/** @throws Exception If failed. */
  public void testCreateFileColocated() throws Exception {
    GridGgfsPath path = new GridGgfsPath("/colocated");

    UUID uuid = UUID.randomUUID();

    GridUuid affKey;

    long idx = 0;

    while (true) {
      affKey = new GridUuid(uuid, idx);

      if (grid(0).mapKeyToNode(DATA_CACHE_NAME, affKey).id().equals(grid(0).localNode().id()))
        break;

      idx++;
    }

    try (GridGgfsOutputStream out = fs.create(path, 1024, true, affKey, 0, 1024, null)) {
      // Write 5M, should be enough to test distribution.
      for (int i = 0; i < 15; i++) out.write(new byte[1024 * 1024]);
    }

    GridGgfsFile info = fs.info(path);

    Collection<GridGgfsBlockLocation> affNodes = fs.affinity(path, 0, info.length());

    assertEquals(1, affNodes.size());
    Collection<UUID> nodeIds = F.first(affNodes).nodeIds();

    assertEquals(1, nodeIds.size());
    assertEquals(grid(0).localNode().id(), F.first(nodeIds));
  }
  /**
   * Test file creation.
   *
   * @param path Path to file to store.
   * @param size Size of file to store.
   * @param salt Salt for file content generation.
   * @throws Exception In case of any exception.
   */
  private void testCreateFile(final GridGgfsPath path, final long size, final int salt)
      throws Exception {
    info("Create file [path=" + path + ", size=" + size + ", salt=" + salt + ']');

    final AtomicInteger cnt = new AtomicInteger(0);
    final Collection<GridGgfsPath> cleanUp = new ConcurrentLinkedQueue<>();

    long time =
        runMultiThreaded(
            new Callable<Object>() {
              @Override
              public Object call() throws Exception {
                int id = cnt.incrementAndGet();

                GridGgfsPath f = new GridGgfsPath(path.parent(), "asdf" + (id > 1 ? "-" + id : ""));

                try (GridGgfsOutputStream out = fs.create(f, 0, true, null, 0, 1024, null)) {
                  assertNotNull(out);

                  cleanUp.add(f); // Add all created into cleanup list.

                  U.copy(new GridGgfsTestInputStream(size, salt), out);
                }

                return null;
              }
            },
            WRITING_THREADS_CNT,
            "perform-multi-thread-writing");

    if (time > 0) {
      double rate = size * 1000. / time / 1024 / 1024;

      info(
          String.format(
              "Write file [path=%s, size=%d kB, rate=%2.1f MB/s]",
              path, WRITING_THREADS_CNT * size / 1024, WRITING_THREADS_CNT * rate));
    }

    info("Read and validate saved file: " + path);

    final InputStream expIn = new GridGgfsTestInputStream(size, salt);
    final GridGgfsInputStream actIn = fs.open(path, CFG_BLOCK_SIZE * READING_THREADS_CNT * 11 / 10);

    // Validate continuous reading of whole file.
    assertEqualStreams(expIn, actIn, size, null);

    // Validate random seek and reading.
    final Random rnd = new Random();

    runMultiThreaded(
        new Callable<Object>() {
          @Override
          public Object call() throws Exception {
            long skip = Math.abs(rnd.nextLong() % (size + 1));
            long range = Math.min(size - skip, rnd.nextInt(CFG_BLOCK_SIZE * 400));

            assertEqualStreams(new GridGgfsTestInputStream(size, salt), actIn, range, skip);

            return null;
          }
        },
        READING_THREADS_CNT,
        "validate-multi-thread-reading");

    expIn.close();
    actIn.close();

    info("Get stored file info: " + path);

    GridGgfsFile desc = fs.info(path);

    info("Validate stored file info: " + desc);

    assertNotNull(desc);

    if (log.isDebugEnabled()) log.debug("File descriptor: " + desc);

    Collection<GridGgfsBlockLocation> aff = fs.affinity(path, 0, desc.length());

    assertFalse("Affinity: " + aff, desc.length() != 0 && aff.isEmpty());

    int blockSize = desc.blockSize();

    assertEquals("File size", size, desc.length());
    assertEquals("Binary block size", CFG_BLOCK_SIZE, blockSize);
    // assertEquals("Permission", "rwxr-xr-x", desc.getPermission().toString());
    // assertEquals("Permission sticky bit marks this is file", false,
    // desc.getPermission().getStickyBit());
    assertEquals("Type", true, desc.isFile());
    assertEquals("Type", false, desc.isDirectory());

    info("Cleanup files: " + cleanUp);

    for (GridGgfsPath f : cleanUp) {
      fs.delete(f, true);
      assertNull(fs.info(f));
    }
  }