assertFalse(thumbnailGenerator.generate(thumbnailId, invalidOutputFile));

        // Cleanup
        readOnlyDir.setWritable(true);
    }

    public void test_isTarget_withSupportedMimeType() {
        // Test with supported document type
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("mimetype", "application/pdf");
        assertTrue(thumbnailGenerator.isTarget(docMap));