javascript - Example of how to test a component that uses useQuery? - Stack Overflow

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I have a React ponent that uses the Apollo hooks lib's useQuery hook. I'm having trouble testing this ponent. Here is my current setup.

import React from 'react';
import { BrowserRouter as Router } from 'react-router-dom';
import DashboardBar from './DashboardBar';
import { render, cleanup } from '@testing-library/react';
import { QUERY } from '../../queries';
import { ApolloClient } from 'apollo-client';
import { ApolloProvider as ApolloHooksProvider } from '@apollo/react-hooks';
import { MockedProvider } from 'react-apollo/test-utils';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { MockLink } from 'apollo-link-mock';
import wait from 'waait';
import casual from 'casual';

describe('<DashboardBar />', () => {
  it('renders and matches snapshot', async () => {
    const mocks = [
      {
        request: { query: QUERY, variables: { id: 'WLYhM' } },
        result: {
          data: {
            q: {
              brand: fakeBrand,
              claimByAction: casual.boolean,
              claimRules: fakeClaimRules,
              wantIn: fakeWantIn,
            },
          },
        },
      },
    ];

    function createClient(mocks) {
      return new ApolloClient({
        cache: new InMemoryCache(),
        link: new MockLink(mocks),
      });
    }

    const client = createClient(mocks);

    const { container } = render(
      <ApolloHooksProvider client={client}>
        <Router>
          <DashboardBar {...props} store={reduxStore.store} />
        </Router>
      </ApolloHooksProvider>
    );

    console.log(container.firstChild);
    expect(container.firstChild).toBe(null);

    await wait(200);

    console.log(container.firstChild);
  });
});

When I run the test, I'm getting the following error

TypeError: Cannot read property 'q' of undefined

Even though the data is being returned fine in the actual ponent.

Does anyone have an example of how the successfully set up and executed tests w/ ponents using hooks from the Apollo hooks lib?

Thanks!

I have a React ponent that uses the Apollo hooks lib's useQuery hook. I'm having trouble testing this ponent. Here is my current setup.

import React from 'react';
import { BrowserRouter as Router } from 'react-router-dom';
import DashboardBar from './DashboardBar';
import { render, cleanup } from '@testing-library/react';
import { QUERY } from '../../queries';
import { ApolloClient } from 'apollo-client';
import { ApolloProvider as ApolloHooksProvider } from '@apollo/react-hooks';
import { MockedProvider } from 'react-apollo/test-utils';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { MockLink } from 'apollo-link-mock';
import wait from 'waait';
import casual from 'casual';

describe('<DashboardBar />', () => {
  it('renders and matches snapshot', async () => {
    const mocks = [
      {
        request: { query: QUERY, variables: { id: 'WLYhM' } },
        result: {
          data: {
            q: {
              brand: fakeBrand,
              claimByAction: casual.boolean,
              claimRules: fakeClaimRules,
              wantIn: fakeWantIn,
            },
          },
        },
      },
    ];

    function createClient(mocks) {
      return new ApolloClient({
        cache: new InMemoryCache(),
        link: new MockLink(mocks),
      });
    }

    const client = createClient(mocks);

    const { container } = render(
      <ApolloHooksProvider client={client}>
        <Router>
          <DashboardBar {...props} store={reduxStore.store} />
        </Router>
      </ApolloHooksProvider>
    );

    console.log(container.firstChild);
    expect(container.firstChild).toBe(null);

    await wait(200);

    console.log(container.firstChild);
  });
});

When I run the test, I'm getting the following error

TypeError: Cannot read property 'q' of undefined

Even though the data is being returned fine in the actual ponent.

Does anyone have an example of how the successfully set up and executed tests w/ ponents using hooks from the Apollo hooks lib?

Thanks!

• javascript
• reactjs
• react-hooks
• react-apollo
• react-apollo-hooks

Share Improve this question Follow asked Jul 16, 2019 at 15:33 maxwellgovermaxwellgover 7,15199 gold badges4141 silver badges6666 bronze badges 1

• I think you should use MockedProvider from '@apollo/react-testing' however i've hit the same issues as you on this one – Damian Green Commented Jul 26, 2019 at 16:35

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 4

Actually I managed to get this working using act()

Example as follows:

import { MockedProvider } from '@apollo/react-testing'
import query from 'data/graphql/Device/psaButton.graphql'
import React from 'react'
import { act, create, ReactTestRenderer } from 'react-test-renderer'
import { MockAppNoLayout } from 'testHelpers/testHelpers'
import waitForExpect from 'wait-for-expect'
import PSAButton from './PSAButton'

const mocks = [
  {
    request: {
      query,
      variables: {
        deviceId: '1',
      },
    },
    result: {
      data: {
        deviceById: {
          id: '1',
          info: {
            psaUrl: 'asdsadsad',
            lastSyncDate: 'asdasd',
            lastVerifyDate: 'asdsad',
          },
        },
        user: {
          timeZone: 'Europe/London',
        },
      },
    },
  },
]

describe('PSAButton', () => {
  it('renders correctly', async () => {
    let wrapper: ReactTestRenderer
    act(() => {
      wrapper = create(
        <MockAppNoLayout>
          <MockedProvider mocks={mocks} addTypename={false}>
            <PSAButton deviceId="1" />
          </MockedProvider>
        </MockAppNoLayout>,
      )
    })

    await waitForExpect(() => {
      const testInstance = wrapper.root
      expect(testInstance.findByType('span').children[0]).toBe('Open In PSA')
    })
  })
})

MockAppNoLayout is a React ponent tree containing amock IntlProvider and Styleprovider and the such like, (not important for this question).

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