使用jest的mock函数模拟useQuery或useLazyQuery的返回值， 然后使用MockedProvider来包装测试组件。在测试中，我们需要wrap our component inside a MockedProvider 并且传入client 属性，这里使用mock的client.

示例代码：

import { MockedProvider } from '@apollo/client/testing';
import { useLazyQuery } from '@apollo/client';

const GET_USERS = gql`
  query getUsers($id: ID!) {
    user(id: $id) {
      id
      username
    }
  }
`;

describe('User component', () => {
  const mocks = [
    {
      request: {
        query: GET_USERS,
        variables: {
          id: 1,
        },
      },
      result: {
        data: {
          user: {
            id: 1,
            username: 'testUser',
          },
        },
      },
    },
  ];

  const mockUserComponent = () => {
    const [getUsers, { data }] = useLazyQuery(GET_USERS, {
      onCompleted: () => {
        console.log('Data fetched');
      },
    });

    return (
      

         getUsers({ variables: { id: 1 } })}>
          Get User
        
        {data && 
{data.user.username}
}
      
    );
  };

  it('fetches user data on button click', async () => {
    const { getByText } = render(
      
        {mockUserComponent()}
      ,
    );
    
    fireEvent.click(getByText(/get user/i));
    
    await waitFor(() => {
      expect(getByText(/testuser/i)).toBeInTheDocument();
    });
  });
});