long elapsed = endTime - startTime;
        assertTrue("Expected minimal sleep time, got " + elapsed + "ms", elapsed < 50);
    }

    @Test
    public void test_waitForNext_withNegativeInterval() {
        configHelper.setReloadInterval(-100L);

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