Redux Test Store

createTestStore.js

export const createTestStore = (
  reducer,
  initialState = {},
  path = [],
  thunkArguments = {}
) => {
  const stateHistory = [];
  const dispatchHistory = [];

  const logHistory = store => next => action => {
    dispatchHistory.push(action);

    if (action.type) {
      stateHistory.push(store.getState());
    }

    return next(action);
  };

  const middleware = applyMiddleware(
    logHistory,
    thunk.withExtraArgument(thunkArguments)
  );
  const reducers = path.reduceRight(
    (acc, item) => combineReducers({ [item]: acc }),
    reducer
  );
  const initial = path.reduceRight(
    (acc, item) => ({ [item]: acc }),
    initialState
  );

  const store = createReduxStore(reducers, initial, middleware);

  const getPath = state => path.reduce((acc, item) => acc[item], state);

  return {
    ...store,
    dispatch: jest.fn(store.dispatch),
    subscribe: jest.fn(store.subscribe),
    getLocalState: () => getPath(store.getState()),
    getStateHistory: () => [...stateHistory, store.getState()].map(getPath),
    getDispatchHistory: () => [...dispatchHistory]
  };
};