Object result2 = scriptExecutor.execute("modifyEngine", "script2");
        assertEquals(2, result2); // Should still be 2, not accumulating
    }

    @Test
    public void test_shutdown_withListener() {
        // Add shutdown listener
        TestShutdownListener listener = new TestShutdownListener();
        scriptExecutor.addShutdownListener(listener);

        // Verify listener not called yet