ошибка в тесте избыточного действия

Если вы хотите протестировать создателей действий, вам следует имитировать метод followApi.handleFavorite, а не axios.

Вот решение для тестирования создателей действий, использующих только jestjs и typescript. Вы можете смоделировать модуль вручную самостоятельно.

Структура папки:

.
├── actionCreators.spec.ts
├── actionCreators.ts
├── followApi.ts
└── httpServise.ts

actionCreators.ts:

import followApi from './followApi';

export const handleFavorite = data => {
  return dispatch => {
    return followApi.handleFavorite(data).then(
      payload => {
        dispatch({ type: 'HANDLE_FAVORITE_SUCCESS', payload });
      },
      err => {
        dispatch({ type: 'ERROR', payload: err });
      }
    );
  };
};

followApi.ts:

import { httpServise } from './httpServise';

const host = 'http://github.com/mrdulin';
const port = 3000;

const followApi = {
  handleFavorite: data => {
    return new Promise((resolve, reject) => {
      httpServise.patch(`${host}:${port}/followings/handle-favorite`, data).then(
        (res: any) => {
          if (res.data.payload) {
            resolve(res.data.payload);
          } else {
            reject({ status: 401 });
          }
        },
        err => reject(err)
      );
    });
  }
};

export default followApi;

httpService.ts:

import axios from 'axios';

function getHeaders() {
  return {};
}

export const httpServise = {
  patch: (url, params) => {
    return new Promise((resolve, reject) => {
      axios(url, {
        method: 'PATCH',
        headers: getHeaders(),
        data: params
      }).then(
        res => {
          resolve(res);
        },
        err => {
          reject(err);
        }
      );
    });
  }
};

actionCreators.spec.ts:

import configureMockStore from 'redux-mock-store';
import thunk, { ThunkDispatch } from 'redux-thunk';
import { AnyAction } from 'redux';
import * as actions from './actionCreators';
import followApi from './followApi';

jest.mock('./followApi.ts', () => {
  return {
    handleFavorite: jest.fn()
  };
});

type State = any;
const middlewares = [thunk];
const mockStore = configureMockStore<State, ThunkDispatch<State, undefined, AnyAction>>(middlewares);
const store = mockStore();

describe('followings actions', () => {
  beforeEach(() => {
    store.clearActions();
    jest.resetAllMocks();
  });
  it('dispatches the HANDLE_FAVORITE_SUCCESS action', () => {
    expect.assertions(2);
    const mockedHandleFavoritePayload = {
      followingInfoId: '1',
      checked: true
    };
    (followApi.handleFavorite as jest.MockedFunction<typeof followApi.handleFavorite>).mockResolvedValueOnce(
      mockedHandleFavoritePayload
    );
    const data = 'jest';
    const expectedActions = [
      {
        type: 'HANDLE_FAVORITE_SUCCESS',
        payload: {
          followingInfoId: '1',
          checked: true
        }
      }
    ];
    return store.dispatch(actions.handleFavorite(data)).then(() => {
      expect(store.getActions()).toEqual(expectedActions);
      expect(followApi.handleFavorite).toBeCalledWith(data);
    });
  });

  it('dispatches the ERROR action', () => {
    const mockedhHndleFavoriteError = new Error('network error');
    (followApi.handleFavorite as jest.MockedFunction<typeof followApi.handleFavorite>).mockRejectedValueOnce(
      mockedhHndleFavoriteError
    );
    const data = 'jest';
    const expectedActions = [
      {
        type: 'ERROR',
        payload: mockedhHndleFavoriteError
      }
    ];
    return store.dispatch(actions.handleFavorite(data)).then(() => {
      expect(store.getActions()).toEqual(expectedActions);
      expect(followApi.handleFavorite).toBeCalledWith(data);
    });
  });
});

Результат модульного теста с отчетом о 100% покрытии:

PASS  src/stackoverflow/52025257/actionCreators.spec.ts (5.95s)
  followings actions
    ✓ dispatches the HANDLE_FAVORITE_SUCCESS action (5ms)
    ✓ dispatches the ERROR action (2ms)

-------------------|----------|----------|----------|----------|-------------------|
File               |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-------------------|----------|----------|----------|----------|-------------------|
All files          |      100 |      100 |      100 |      100 |                   |
 actionCreators.ts |      100 |      100 |      100 |      100 |                   |
-------------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        6.87s, estimated 7s

Исходный код: https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/52025257