assertNotNull(retrieved);
        assertEquals(engine, retrieved);
    }

    // Test concurrent-like scenario (sequential but simulating concurrent behavior)
    public void test_add_multipleSameNameSequential() {
        TestScriptEngine engine1 = new TestScriptEngine("v1");
        TestScriptEngine engine2 = new TestScriptEngine("v2");
        TestScriptEngine engine3 = new TestScriptEngine("v3");