// Test null input
        assertEquals("null", InputValidator.sanitizeForLogging(null));

        // Test normal string without control characters
        assertEquals("test", InputValidator.sanitizeForLogging("test"));

        // Test removal of control characters (they are removed, not replaced with spaces)
        assertEquals("teststring", InputValidator.sanitizeForLogging("test\0string"));

     * Sanitizes a string for safe logging (removes control characters)
     *
     * @param input the string to sanitize
     * @return sanitized string safe for logging
     */
    public static String sanitizeForLogging(String input) {
        if (input == null) {
            return "null";
        }
        // Remove control characters and limit length
        String sanitized = input.replaceAll("[\\x00-\\x1f]", "");