fail("Expected RuntimeException");
        } catch (RuntimeException e) {
            assertEquals("Test exception", e.getMessage());
        }
    }

    @Test
    public void test_addShutdownListener_null() {
        // Test adding null listener
        jobExecutor.addShutdownListener(null);
        assertNull(jobExecutor.shutdownListener);

        // Verify only second listener was called
        assertFalse(listener1.wasShutdownCalled());
        assertTrue(listener2.wasShutdownCalled());
    }

    @Test
    public void test_addShutdownListener_null() {
        // Add null listener
        scriptExecutor.addShutdownListener(null);

        // Try to shutdown
        try {
            scriptExecutor.shutdown();