dir1.mkdirs();
        File expiredFile = new File(dir1, "expired.png");
        expiredFile.createNewFile();
        expiredFile.setLastModified(System.currentTimeMillis() - 10000L);

        File recentFile = new File(dir1, "recent.png");
        recentFile.createNewFile();
        recentFile.setLastModified(System.currentTimeMillis());

        // Override purge to avoid client operations

        File jar1 = new File(libDir, "test1.jar");
        File jar2 = new File(libDir, "test2.JAR");
        File notJar = new File(libDir, "test.txt");
        assertTrue(jar1.createNewFile());
        assertTrue(jar2.createNewFile());
        assertTrue(notJar.createNewFile());

        execJob.testAppendJarFile(":", buf, libDir, "/base/path/");

        String result = buf.toString();

                return false;
            }

            // Simulate thumbnail generation
            try {
                if (!outputFile.exists()) {
                    outputFile.createNewFile();
                }
                // Write some dummy content to simulate actual thumbnail
                Files.write(outputFile.toPath(), ("thumbnail-" + thumbnailId).getBytes());
                return true;