assertTrue(result.contains("null") || result.contains("NullPointer"));
    }

    // Test with negative priority
    @Test
    public void test_addScoreBooster_negativePriority() {
        PriorityTrackingBooster booster1 = new PriorityTrackingBooster(-1, 100L);
        PriorityTrackingBooster booster2 = new PriorityTrackingBooster(0, 200L);