@Override
    public String buildContext() {
        final SelectorDO after = (SelectorDO) getAfter();
        if (Objects.isNull(getBefore())) {
            return String.format("the namespace [%s] selector [%s] is %s", after.getNamespaceId(), after.getName(), StringUtils.lowerCase(getType().getType().toString()));
        }
        return String.format("the namespace [%s] selector [%s] is %s : %s", after.getNamespaceId(), after.getName(), StringUtils.lowerCase(getType().getType().toString()), contrast());
        
    }
@Test
    void buildContextAndBeforeNotNullAndNoChange() {
        SelectorChangedEvent selectorChangedEvent
                = new SelectorChangedEvent(before, before, EventTypeEnum.SELECTOR_CREATE, "test-operator");

        String changeMsg = "it no change";
        SelectorDO after = (SelectorDO) selectorChangedEvent.getAfter();
        String expectMsg = String.format("the namespace [%s] selector [%s] is %s : %s", after.getNamespaceId(), after.getName(),
                StringUtils.lowerCase(selectorChangedEvent.getType().getType().toString()), changeMsg);

        String actualMsg = selectorChangedEvent.buildContext();

        assertEquals(expectMsg, actualMsg);
    }