actions4.test.js

// actions.test.js

// Alguns imports importantes:

// Importando o arquivo onde terá a função acoplada à função testada
import * as punkapi from './path/to/file';
// Importando o aquivo onde terá a função testada
import * as actions from './actions';
// Arquivo com as constantes dos types usados nas actions
import * as types from './types';

describe('App actions tests', () => {
  beforeEach(() => {
    jest.resetAllMocks();
  });

  describe('fetchBeers', () => {
    // Testando caso de sucesso
    it('must to return success action on success', () => {
      jest
        .spyOn(punkapi, 'getBeers')
        .mockImplementation(() => Promise.resolve({ data: { mock: 'mock' } }));

      const dispatchMock = jest.fn();

      const promise = actions.fetchBeers()(dispatchMock);

      return promise.then(() => {
        const argOfFirstCall = dispatchMock.mock.calls[0][0];
        const argOfSecondCall = dispatchMock.mock.calls[1][0];

        expect(argOfFirstCall).toEqual({ type: types.FETCH_BEERS });

        expect(argOfSecondCall).toEqual({
          type: types.FETCH_BEERS_SUCCESS,
          payload: { mock: 'mock' },
        });
      });
    });

    // Testando caso de falha
    it('must to return failure action on failure', () => {
      jest
        .spyOn(punkapi, 'getBeers')
        // Mockando com Promise.reject
        .mockImplementation(() => Promise.reject({ error: 'Error' }));

      const dispatchMock = jest.fn();

      const promise = actions.fetchBeers()(dispatchMock);

      return promise.then(() => {
        const argOfFirstCall = dispatchMock.mock.calls[0][0];
        const argOfSecondCall = dispatchMock.mock.calls[1][0];

        expect(argOfFirstCall).toEqual({ type: types.FETCH_BEERS });

        expect(argOfSecondCall).toEqual({
          type: types.FETCH_BEERS_FAILURE,
          error: { error: 'Error' },
        });
      });
    });
  });
});