}

    // Test executeThumbnailGenerator with process failure
    public void test_executeThumbnailGenerator_processFailure() {
        thumbnailJob.numOfThreads(2);

        testProcessHelper.exitValue = 1;
        testProcessHelper.processOutput = "Generation failed";

        try {
            thumbnailJob.executeThumbnailGenerator();
            fail("Should throw JobProcessingException");

            jobExecutor.addShutdownListener(() -> ComponentUtil.getProcessHelper().destroyProcess(sessionId));
        }

        final TimeoutTask timeoutTask = createTimeoutTask();
        try {
            executeThumbnailGenerator();
        } catch (final Exception e) {
            logger.warn("Failed to generate thumbnails.", e);
            resultBuf.append(e.getMessage()).append("\n");
        } finally {