mock.assertLastMethodCalled("submit");
      assertEquals(RESULT_VALUE, f.get());
    }
  }

  public void testInvokeAll() throws InterruptedException, ExecutionException {
    List<Callable<String>> tasks = createTasks(3);
    {
      MockExecutor mock = new MockExecutor();
      TestExecutor testExecutor = new TestExecutor(mock);
      List<Future<String>> futures = testExecutor.invokeAll(tasks);

        assertNull(task);
    }

    public void test_createTask_withEmptyPath() {
        // Test task creation with empty path
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("mimetype", "application/pdf");

        Tuple3<String, String, String> task = thumbnailGenerator.createTask("", docMap);
        assertNull(task);
    }

        // Test createTask method (requires FessConfig)
        generator = new TestThumbnailGenerator();
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("id", "doc123");

        // Since createTask depends on FessConfig, it may not work properly
        // in unit tests without full container
        try {
            generator.createTask("/path/to/thumb.jpg", docMap);

        emptyGenerator.setName("empty");
        String path = "/path/to/thumbnail.jpg";

        // Since createTask requires FessConfig, it may not work properly
        // We test that the method can be called without throwing exceptions
        try {
            emptyGenerator.createTask(path, docMap);
        } catch (Exception e) {
            // Expected when FessConfig is not available
        }
    }

     * @param path The path to the source document.
     * @param docMap The document map containing metadata.
     * @return A tuple containing task information.
     */
    Tuple3<String, String, String> createTask(String path, Map<String, Object> docMap);

                return found;
            });
        } else {
            available = true;
        }
        return available;
    }

    @Override
    public Tuple3<String, String, String> createTask(final String path, final Map<String, Object> docMap) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String thumbnailId = DocumentUtil.getValue(docMap, fessConfig.getIndexFieldId(), String.class);

     * @param docMap the document metadata map containing field values
     * @return a tuple containing the generator name, thumbnail ID, and path
     */
    @Override
    public Tuple3<String, String, String> createTask(final String path, final Map<String, Object> docMap) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String thumbnailId = DocumentUtil.getValue(docMap, fessConfig.getIndexFieldId(), String.class);

        }

        @Override
        public boolean isTarget(Map<String, Object> docMap) {
            return target;
        }

        @Override
        public Tuple3<String, String, String> createTask(String path, Map<String, Object> docMap) {
            return task;
        }

        @Override
        public void destroy() {
            // Do nothing
        }
    }

            if (generator.isTarget(docMap)) {
                final String path = getImageFilename(docMap);
                final Tuple3<String, String, String> task = generator.createTask(path, docMap);
                if (task != null) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("Add thumbnail task: {}", task);
                    }