metamask-extension/test/lib/mock-store.js

import { applyMiddleware, createStore } from 'redux'
import thunkMiddleware from 'redux-thunk'
import { createLogger } from 'redux-logger'

const rootReducer = function () {}

export default configureStore

const loggerMiddleware = createLogger()

const createStoreWithMiddleware = applyMiddleware(
  thunkMiddleware,
  loggerMiddleware
)(createStore)

function configureStore (initialState) {
  return createStoreWithMiddleware(rootReducer, initialState)
}