/**
     * Update the configuration.
     */
    public void update() {
        CommonPoolUtil.execute(this::load);
    }

    /**
     * Wait for the next reloading.
     */
    protected void waitForNext() {
        if (reloadInterval > 0) {
            ThreadUtil.sleep(reloadInterval);
        }
    }

    /**
     * Load the configuration.
     * @return The number of loaded configurations.
     */

    @Test
    public void test_waitForNext_withPositiveInterval() throws InterruptedException {
        configHelper.setReloadInterval(20L);

        long startTime = System.currentTimeMillis();
        configHelper.waitForNext();
        long endTime = System.currentTimeMillis();

        long elapsed = endTime - startTime;
        assertTrue("Expected at least 15ms sleep, got " + elapsed + "ms", elapsed >= 15);