scoreUpdater.addScoreBooster(booster);

        String result = scoreUpdater.execute();
        // NullPointerException message should be captured
        assertTrue(result.contains("null") || result.contains("NullPointer"));
    }

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