我有这个组件，可以从阿波罗缓存中获取添加的项目。我有一个从添加的项目数组中删除项目的方法 我正在努力为此编写测试。.所以下面是我编写的组件：

const GET_ADDED_ITEMS = gql`
  query GetaddedItems{
    addedItems @client {
      id
      name
    }
  }
`;

type Props = {
  offer?: Offer,render: RenderProps => any,client: ApolloClient<any>
};

class AddedItems extends React.Component<Props> {
  render() {
    const { offer,render } = this.props;

    const removeItem = (selectedItem) => {
      this.props.client.query({ query: GET_ADDED_ITEMS }).then(({ data = {} }) => {
        const { addedItems } = data;
        const newItems = [ ...addedItems ];
        newItems.splice(addedItems.findIndex(item => item === selectedItem,1));

        this.props.client.writeData({
          data: {
            addedItems: newItems.map(item => ({
              ...item
            }))
          }
        });
      });
    }

    return (
      <Query query={GET_ADDED_ITEMS}>
        {({ data,loading }) => {
          if (loading) return null;
          const { addedItems } = data;

          return render({
            addedItems,removeItem
          });
        }}
      </Query>
    );
  }
}

export default withApollo(AddedItems);

我想测试removeItem方法。我的情况如下：

  it('removes an item',async () => {
    const { getByText,fireEvent } = render(
      <MockedProvider
        mocks={mocks}
        addTypename={false}
      >
        <AddedItems
          offer={offer}
          render={({ addedItems,removeItem }) => (
            <ItemSummaryContainer addedItems={addedItems} removeItem={removeItem}/>
          )}
        />
      </MockedProvider>
    );

    const addedItem = await waitForElement(() => getByText('Point of sale'));
    expect(addedItem).toBeVisible();

  });

我如何测试removeItem方法？而且我猜addItem将像这样expect(addedItem).toBeNull();