// Test with various MIME types
        String[] supportedTypes = { "application/pdf", "image/jpeg", "image/png" };
        String[] unsupportedTypes = { "text/plain", "application/xml", "audio/mp3" };

        for (String mimeType : supportedTypes) {
            Map<String, Object> docMap = new HashMap<>();
            docMap.put("mimetype", mimeType);

                "application/vnd.openxmlformats-officedocument.wordprocessingml.document", "text/html", "text/plain", "application/json",
                "application/xml", "audio/mp3", "video/mp4", "application/postscript" };

        for (final String mimeType : mimeTypes) {
            assertEquals("Extension for " + mimeType + " should be empty", "", generator.getExtensionFromMimeType(mimeType));