Vuexのactionをテストする関数

test-action.ts

import assert from 'assert';

/**
 * VuexにおけるActionHandlerが、期待するMutationをcommitするかをテストする。
 * Vuexの型はこちらを参照 https://github.com/vuejs/vuex/blob/dev/types/index.d.ts
 * @param {*} action テストしたいActionHandler
 * @param {*} payload ActionHandlerに渡すpayload。'skip'を指定でテストを無視できる。
 * @param {object} state ActionHandlerに渡すActionContextのstate
 * @param {array} expectedMutationsAndActions ActionHandlerがcommit/dispatchするオブジェクトの配列。
 * @param {object} additionalParams 任意。ActionHandlerに渡すActionContextの追加プロパティ。
 * @returns {promise} テスト結果をPromiseで返す。
 */
export const testAction = async (
  action: any,
  payload: any,
  state: Object,
  expectedMutationsAndActions: Array<{ type: string; payload?: any }>,
  additionalParams: Object = {},
) => {
  let count = 0;

  const commitAndDispatch = (type, payload) => {
    const mutationsAndActions = expectedMutationsAndActions[count];

    try {
      assert.equal(type, mutationsAndActions.type);
      if (payload && mutationsAndActions.payload !== 'skip') {
        assert.deepEqual(payload, mutationsAndActions.payload);
      }
    } catch (error) {
      console.log(error);
      console.log('actual type', type);
      console.log('actual payload', payload);
      return Promise.reject(false);
    }

    count++;
  };

  await action(
    {
      commit: commitAndDispatch,
      dispatch: commitAndDispatch,
      state,
      ...additionalParams,
    },
    payload,
  );

  if (count < expectedMutationsAndActions.length) {
    return Promise.reject(false);
  }
  return Promise.resolve(true);
};

// action.spec.ts
it('get all resources', async () => {
  nock(apiServer())
    .get(SOME_ENDPOINT)
    .query(SOME_QUERY)
    .reply(200, {
      message: 'OK',
      resources: [...]
    });
  const success = await testAction(
    actions.getResources,
    null,
    STATE_MOCK,
    [
      { type: 'request' },
      {
        type: 'success',
        payload: {
          resources: [...]
        },
      },
    ],
    { rootState: ROOT_STATE_MOCK },
  );
  expect(success).toBe(true);
});