some cleaning and started to understand unittest with jest

src/store/index.js

@@ -2,16 +2,11 @@ import Vue from 'vue'
 import Vuex from 'vuex'
 import posts from './modules/posts'
 
-Vue.use(Vuex)
-
 // https://github.com/vuejs/vuex/tree/dev/examples/shopping-cart
 
-// const debug = process.env.NODE_ENV !== 'production'
-
+Vue.use(Vuex)
 export default new Vuex.Store({
   modules: {
     posts
   }
-  // strict: debug,
-  // plugins: debug ? [createLogger()] : []
 })