assertDoesNotThrow(() -> InputValidator.validateCredits(0));
        assertDoesNotThrow(() -> InputValidator.validateCredits(100));
        assertDoesNotThrow(() -> InputValidator.validateCredits(InputValidator.MAX_CREDITS));

        assertThrows(IllegalArgumentException.class, () -> InputValidator.validateCredits(-1));
        assertThrows(IllegalArgumentException.class, () -> InputValidator.validateCredits(InputValidator.MAX_CREDITS + 1));
    }

    /**
     * Validates SMB credits value
     *
     * @param credits the credits value to validate
     * @throws IllegalArgumentException if credits value is invalid
     */
    public static void validateCredits(int credits) {
        if (credits < 0) {
            throw new IllegalArgumentException("Credits cannot be negative: " + credits);
        }
        if (credits > MAX_CREDITS) {