public String getItemValue(final String key) {
        OpenItemDTO openItemDTO = this.apolloOpenApiClient.getItem(
                apolloConfig.getAppId(),
                apolloConfig.getEnv(),
                apolloConfig.getClusterName(),
                apolloConfig.getNamespace(),
                key
        );
        return openItemDTO.getValue();
    }
@Test
    public void testGetItemValue() {
        when(apolloClient.getItemValue(Mockito.any())).thenReturn("42");
        assertEquals("42", apolloClient.getItemValue("Key"));
        verify(apolloClient).getItemValue(Mockito.any());
    }