Map<String, Object> docMap = new HashMap<>();
        docMap.put("mimetype", "application/pdf");
        assertTrue(thumbnailGenerator.isTarget(docMap));
    }

    public void test_isTarget_withUnsupportedMimeType() {
        // Test with unsupported document type
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("mimetype", "application/unknown");