How to write test that mocks the $route object in vue components

Question

I have a component that contains statement like this.$route.fullPath, how should I mock value of fullPathof $route object if I want to test that component?

Answer 1

I disagree with the top answer - you can mock $route without any issue.

On the other hand, installing vue-router multiple times on the base constructor will cause you problems. It adds $route and $router as read only properties. Which makes it impossible to overwrite them in future tests.

There are two ways to achieve this with vue-test-utils.

Mocking vue-router with the mocks option

const $route = {
    fullPath: 'full/path'
}
const wrapper = mount(ComponentWithRouter, { 
  mocks: {
    $route
  } 
})

wrapper.vm.$route.fullPath // 'full/path'

You can also install Vue Router safely by using createLocalVue:

Installing vue-router safely in tests with createLocalVue

const localVue = createLocalVue()
localVue.use(VueRouter)
const routes = [
 {
   path: '/',
   component: Component
 }
]
const router = new VueRouter({
 routes
})
const wrapper = mount(ComponentWithRouter, { localVue, router })
expect(wrapper.vm.$route).to.be.an('object')

Answer 2

Best not mock vue-router but rather use it to render the component, that way you get a proper working router. Example:

import Vue from 'vue'
import VueRouter from 'vue-router'
import totest from 'src/components/totest'

describe('totest.vue', () => {
  it('should totest renders stuff', done => {
    Vue.use(VueRouter)
    const router = new VueRouter({routes: [
        {path: '/totest/:id', name: 'totest', component: totest},
        {path: '/wherever', name: 'another_component', component: {render: h => '-'}},
    ]})
    const vm = new Vue({
      el: document.createElement('div'),
      router: router,
      render: h => h('router-view')
    })
    router.push({name: 'totest', params: {id: 123}})
    Vue.nextTick(() => {
      console.log('html:', vm.$el)
      expect(vm.$el.querySelector('h2').textContent).to.equal('Fred Bloggs')
      done()
    })
  })
})

Things to note:

1. I'm using the runtime-only version of vue, hence render: h => h('router-view').
2. I'm only testing the totest component, but others might be required if they're referenced by totest eg. another_component in this example.
3. You need nextTick for the HTML to have rendered before you can look at it/test it.

One of the problems is that most of the examples I found referred to the old version of vue-router, see the migrations docs, eg. some examples use router.go() which now doesn't work.

Answer 3

No answer was helping me out, So I dig into vue-test-utils documentation and found myself a working answer, so you need to import.

import { shallowMount,createLocalVue } from '@vue/test-utils';
import router from '@/router.ts';
const localVue = createLocalVue();

We created a sample vue instance. While testing you need to use shallowMount so you can provide vue app instance and router.

describe('Components', () => {
  it('renders a comment form', () => {
    const COMMENTFORM = shallowMount(CommentForm,{
      localVue,
      router
    });
  })
})

You can easily pass router and to shallow mount and it does not gives you the error. If you want to pass store you use:

import { shallowMount,createLocalVue } from '@vue/test-utils';
import router from '@/router.ts';
import store from '@/store.ts';
const localVue = createLocalVue();

And then pass store:

describe('Components', () => {
  it('renders a comment form', () => {
    const COMMENTFORM = shallowMount(CommentForm,{
      localVue,
      router,
      store
    });
  })
})

This solution solved the following errors:

• Cannot read property 'params' of undefined when using this.$route.params.id
• Unknown custom element router-link

✔

Answer 4

Easiest method i found is to use localVue

import { createLocalVue, mount } from '@vue/test-utils';
import VueRouter from 'vue-router';
import Vuex from 'vuex';

import ComponentName from '@/components/ComponentName.vue';
// Add store file if any getters is accessed
import store from '@/store/store';

describe('File name', () => {
  const localVue = createLocalVue();
  localVue.use(VueRouter);

  // Can also be replaced with route(router.js) file
  const routes = [
    {
      path: '/path',
      component: ComponentName,
      name: 'Route name'
    }
  ];

  const router = new VueRouter({ routes });

  // if needed
  router.push({
    name: 'Route name',
    params: {}
  });

  const wrapper = mount(ComponentName, {
    localVue,
    router,
    store
  });

  test('Method()', () => {
    wrapper.vm.methodName();

    expect(wrapper.vm.$route.path)
      .toEqual(routes[0].path);
  });
});

Hope it helps!!!

Answer 5

Why are all answers so complicated? You can just do:

...
wrapper = mount(HappyComponent, {
  mocks: {
    $route: { fullPath: '' }
  },
})
...

Answer 6

You dont have to specifically "mock" a router. Your application can set VueRouter in the global vue scope and you can still make it do what you want in your tests without issue.

Read the localVue usage with VueRouter: https://vue-test-utils.vuejs.org/guides/#using-with-vue-router.

I am currently pulling in a complex router from our main app and am able to jest.spyOn() calls to router.push() as well as setting the path before the component is created running shallowMount() for some route handling in a created() hook.

The Workaround

// someVueComponent.vue

<template>
... something
</template>
<script>
...
data () {
  return {
    authenticated: false
  }
},
...
created () {
  if(!this.authenticated && this.$route.path !== '/'){
    this.$router.push('/')
  }
}
</script>

// someVueComponent.spec.js

import Vuex from 'vuex'
import VueRouter from 'vue-router'
import { shallowMount, createLocalVue } from '@vue/test-utils'
import SomeVueComponent from 'MyApp/components/someVueComponent'
import MyAppRouter from 'MyApp/router'
import MyAppCreateStore from 'MyApp/createStore'
import merge from 'lodash.merge'

function setVueUseValues (localVue) {
  localVue.use(Vuex)
  localVue.use(VueRouter)
  // other things here like custom directives, etc
}

beforeEach(() => {
  // reset your localVue reference before each test if you need something reset like a custom directive, etc
  localVue = createLocalVue()
  setVueUseValues(localVue)
})

let localVue = createLocalVue()
setVueUseValues(localVue)

test('my app does not react to path because its default is "/"', () => {
  const options = {
    localVue,
    router: MyAppRouter,
    store: MyAppCreateStore()  
  }  

  const routerPushSpy = jest.spyOn(options.router, 'push')
  const wrapper = shallowMount(SomeVueComponent, options)
  expect(routerPushSpy).toHaveBeenCalledTimes(0)
})

test('my app reacts to path because its not "/" and were not authenticated', () => {
  const options = {
    localVue,
    router: MyAppRouter,
    store: MyAppCreateStore()  
  }

  const routerPushSpy = jest.spyOn(options.router, 'push')
  options.router.push('/nothomepath')
  expect(routerPushSpy).toHaveBeenCalledWith('/nothomepath') // <- SomeVueComponent created hook will have $route === '/nothomepath' as well as fullPath

  const wrapper = shallowMount(SomeVueComponent, options)
  expect(routerPushSpy).toHaveBeenCalledWith('/') // <- works
})

The above is done with the idea that I need the $route state changed before SomeVueComponent.vue is created/mounted. Assuming you can create the wrapper and want to test that the component this.$router.push('/something') based on some other state or action you can always spy on the wrapper.vm instance

let routerPushSpy = jest.spyOn(wrapper.vm.$router, 'push') // or before hooks, etc

As of this writing there seems to be an open defect which keeps the following from working because vm.$route will always be undefined, making the above the only option (that I know of) as there is no other way to "mock" the $route because installing VueRouter writes read only properties to $route.

From the vue-test-utils docs https://vue-test-utils.vuejs.org/guides/#mocking-route-and-router:

import { shallowMount } from '@vue/test-utils'

const $route = {
  path: '/some/path'
}

const wrapper = shallowMount(Component, {
  mocks: {
    $route
  }
})

wrapper.vm.$route.path // /some/path

If your interested here is the github link to a reproduction of the issue: https://github.com/vuejs/vue-test-utils/issues/1136

Answer 7

All kudos to @SColvin for his answer; helped find an answer in my scenario wherein I had a component with a router-link that was throwing a

ERROR: '[Vue warn]: Error in render function: (found in <RouterLink>)'

during unit test because Vue hadn't been supplied with a router. Using @SColvin answer to rewrite the test originally supplied by vue-cli from

describe('Hello.vue', () =>
{
  it('should render correct contents', () =>
  {
    const Constructor = Vue.extend(Hello);
    const vm = new Constructor().$mount();
    expect(vm.$el.querySelector('.hello h1').textContent)
      .to.equal('Welcome to Your Vue.js App');
  });

to

describe('Hello.vue', () =>
{
  it('should render correct contents', () =>
  {
    Vue.use(VueRouter);
    const router = new VueRouter({
      routes: [
        { path: '/', name: 'Hello', component: Hello },
      ],
    });
    const vm = new Vue({
      el: document.createElement('div'),
      /* eslint-disable object-shorthand */
      router: router,
      render: h => h('router-view'),
    });
    expect(vm.$el.querySelector('.hello h1').textContent)
      .to.equal('Welcome to Your Vue.js App');
  });
});

Not needing to pass parameters in to the view I could simplify the component as the default render, no need to push and no need to wait nextTick. HTH someone else!

Answer 8

Adding to the great answer from @SColvin, here's an example of this working using Avoriaz:

import { mount } from 'avoriaz'
import Vue from 'vue'
import VueRouter from 'vue-router'
import router from '@/router'
import HappyComponent from '@/components/HappyComponent'

Vue.use(VueRouter)

describe('HappyComponent.vue', () => {
  it('renders router links', () => {
    wrapper = mount(HappyComponent, {router})
    // Write your test
  })
})

I believe this should work with vue-test-utils, too.

Answer 9

Take a look at this example using vue-test-utils, where I'm mocking both router and store.

import ArticleDetails from '@/components/ArticleDetails'
import { mount } from 'vue-test-utils'
import router from '@/router'

describe('ArticleDetails.vue', () => {
  it('should display post details', () => {
    const POST_MESSAGE = 'Header of our content!'

    const EXAMPLE_POST = {
      title: 'Title',
      date: '6 May 2016',
      content: `# ${POST_MESSAGE}`
    }

    const wrapper = mount(ArticleDetails, {
      router,

      mocks: {
        $store: {
          getters: {
            getPostById () {
              return EXAMPLE_POST
            }
          }
        }
      }
    })

    expect(wrapper.vm.$el.querySelector('h1.post-title').textContent.trim()).to.equal(EXAMPLE_POST.title)
    expect(wrapper.vm.$el.querySelector('time').textContent.trim()).to.equal(EXAMPLE_POST.date)
    expect(wrapper.vm.$el.querySelector('.post-content').innerHTML.trim()).to.equal(
      `<h1>${POST_MESSAGE}</h1>`
    )
  })
})

Answer 10

This is what I've been doing as per this article:

it('renders $router.name', () => {
    const scopedVue = Vue.extend();

    const mockRoute = {
        name: 'abc'
    };

    scopedVue.prototype.$route = mockRoute;

    const Constructor = scopedVue.extend(Component);
    const vm = new Constructor().$mount();
    expect(vm.$el.textContent).to.equal('abc');
});

Answer 11

You can mock to vm.$router by setting vm._routerRoot._router

For example

var Constructor      = Vue.extend(Your_Component)
var vm               = new Constructor().$mount()
var your_mock_router = {hello:'there'}

vm.$router             = your_mock_router //An error 'setting a property that has only a getter'
vm._routerRoot._router = your_mock_router //Wow, it works!

You can double check their source code here: https://github.com/vuejs/vue-router/blob/dev/dist/vue-router.js#L558

Answer 12

Easiest way i've found is to mock the $route.

it('renders $router.name', () => {
  const $route = {
    name: 'test name - avoriaz'
  }


 const wrapper = shallow(Component, {
    mocks: {
      $route
    }
  })
  expect(wrapper.text()).to.equal($route.name)
})