title: VueJS - Unit testing with vue-test-utils gives error - TypeError: _vm.$t is not a function
body: <p>Relatively new to Vuejs and testing its components. Using vue-test-utils and jest for testing. Getting following error 
  <a href="https://i.stack.imgur.com/rQejp.jpg" rel="noreferrer">test log</a></p>
  
  <p>The .vue file consists of template, component and styling. Below is the part of the SignupLayout.vue that gets error - </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;style lang="sass"&gt;
  @import '../stylesheets/colors'
  html[path="/signup"], html[path="/login"]
    height: 100%
    background-image: url("../assets/background.jpg")
    background-size: cover
    background-position: center
    background-repeat: no-repeat
    overflow: hidden
  
    #signup-layout
      #change-language-button
        .lang-menu
          color: $alto
  
  &lt;/style&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>Test File - </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>import Vue from 'vue';
  import Vuex from 'vuex'
  import SignupLayout from '../src/components/SignupLayout.vue';
  import { mount, shallow, createLocalVue } from '@vue/test-utils';
  
  const localVue = createLocalVue()
  
  localVue.use(Vuex)
  
  jest.resetModules()
  
  describe('Signup.test.js', () =&gt; {
      let cmp
      let actions
      let store
      let getters
      let state
  
      beforeEach(() =&gt; {
  
  
          state = {
              email: 'abc@gmail.com'
          }
   
          getters = {
              CURRENT_USER_EMAIL: state =&gt; state.email
          }
  
          store = new Vuex.Store({
              getters
          })
  
  
      })
  
      it('has received ["Login"] as the title property', () =&gt; {
          cmp = shallow(SignupLayout, {
              store,
              localVue,
              propsData: {
                  title: ['Login']
              },
              data: {
                  email: 'abc@dsf.com'
              }
          })
          cmp.update()
          expect(cmp.vm.title).toEqual(['Login'])
      })
  
  
  })</code></pre>
  </div>
  </div>
  </p>
  
  <p>Confused as to what has $t got to do with sass. Any help would be appreciated. Stuck here for a while now.
  Let me know if more details needed. Thanks in advance</p>