@Override
    public String toString() {
        return "ConfigChangeItem{" + "key='" + key + '\'' + ", oldValue='" + oldValue + '\'' + ", newValue='" + newValue
                + '\'' + ", type=" + type + '}';
    }
@Test
    void testToString() {
        ConfigChangeItem item = new ConfigChangeItem("testKey", null, "testValue");
        item.setType(PropertyChangeType.ADDED);
        assertEquals("ConfigChangeItem{key='testKey', oldValue='null', newValue='testValue', type=ADDED}",
                item.toString());
    }