In my component set
data(){
categories: this.$parent.categories => which I set in main.js
}
Code file main.js
import categories from '../config/categories';
new Vue({
router,
data: {
categories: categories
}
});
I created 1 function unit test
it(‘check component is a button’,() => {
const wrapper = shallow(FormSearch);
expect(wrapper.contains(‘button’)).toBe(true);
});
I run test then show error: Error in data(): "TypeError: Cannot read property ‘categories’ of undefined"
How to fix it. Help me.
Why not import you categories config file directly into your component?
import Categories from '../config/categories'
then your data method can directly access it:
data () { return { categories: Categories }}
You'll find that much easier to test
yes, thanks you. I changed. I run test then it happens error other
Cannot find module '../../config/categories' from 'mycomponet.vue'.
Although. I run project on browser just working well.
How to fix it. Thanks you very much
For Testing , you can set mock data to escape undefined error while testing . But it is not standard solution .....
it(‘check component is a button’,() => {
const wrapper = shallow(FormSearch);
let mockCategories = { // mock category data }
wrapper.$parent = {
categories: mockCategories
}
expect(wrapper.contains(‘button’)).toBe(true);
});
Try this approach:
const Parent = {
data: () => ({
val: true
}),
template: '<div />'
}
const wrapper = shallowMount(TestComponent, {
parent: Parent
})
Related
I would like to test some custom web components and use jest.js as test runner (due to its support for ES6).
Chromium supports commands like
window.customElements.define('my-custom-element', MyCustomElementClass);
to register a custom web component.
However, window.customElements does not seem to be known in the context of jest tests.
As a work around I tried to use jest in combination with puppeteer and express to run the customElements part in Chromium.
However, I have difficulties to inject the custom element class TreezElement in the evaluated code:
treezElement.js:
class TreezElement extends HTMLElement {
connectedCallback () {
this.innerHTML = 'Hello, World!';
}
}
treezElement.test.js:
import TreezElement from '../../src/components/treezElement.js';
import puppeteer from 'puppeteer';
import express from 'express';
describe('Construction', ()=>{
let port = 3000;
let browser;
let page;
let element;
const width = 800;
const height = 800;
beforeAll(async () => {
const app = await express()
.use((req, res) => {
res.send(
`<!DOCTYPE html>
<html>
<body>
<div id="root"></div>
</body>
</html>`
)
})
.listen(port);
browser = await puppeteer.launch({
headless: false,
slowMo: 80,
args: [`--window-size=${width},${height}`]
});
var pages = await browser.pages();
page = pages[0];
await page.setViewport({ width, height });
await page.goto('http://localhost:3000');
element = await page.evaluate(({TreezElement}) => {
console.log('TreezElement:')
console.log(TreezElement);
window.customElements.define('treez-element', TreezElement);
var element = document.create('treez-element');
document.body.appendChild(element);
return element;
}, {TreezElement});
});
it('TreezElement', ()=>{
});
afterAll(() => {
browser.close();
});
});
Maybe TreezElement is not serializable and therefore undefined is passed to the function.
If I try to import the custom element class TreezElement directly from within the evaluated code ...
element = await page.evaluate(() => {
import TreezElement from '../../src/components/treezElement.js';
console.log('TreezElement:')
console.log(TreezElement);
window.customElements.define('treez-element', TreezElement);
var element = document.create('treez-element');
document.body.appendChild(element);
return element;
});
... I get the error
'import' and 'export' may only appear at the top level
=> What is the recommended way to test custom web components with jest?
Some related stuff:
Web Component / HtmlElement : unit testing
https://itnext.io/testing-your-javascript-in-a-browser-with-jest-puppeteer-express-and-webpack-c998a37ef887
How to mock dependencies for ES6 unit tests?
Can't get test coverage with jest + puppeteer
https://jestjs.io/docs/en/puppeteer
JSDOM 16.2 includes basic support for custom elements and is available in Jest 26.5 and above. Here's a simple Jest test that shows it working:
customElements.define('test-component', class extends HTMLElement {
constructor() {
super();
const p = document.createElement('p')
p.textContent = 'It works!'
this.appendChild(p)
}
})
test('custom elements in JSDOM', () => {
document.body.innerHTML = `<h1>Custom element test</h1> <test-component></test-component>`
expect(document.body.innerHTML).toContain('It works!')
})
Output:
$ jest
PASS ./test.js
✓ custom elements in JSDOM (11 ms)
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 1.409 s
Ran all test suites.
Note not all features are supported yet, notably shadow DOM does not work.
I have created a DOM that supports server side rendering of web components. It also supports testing web components with Jest.
DOM:
https://www.npmjs.com/package/happy-dom
Jest environment:
https://www.npmjs.com/package/jest-environment-happy-dom
To install it
npm install jest-environment-happy-dom --save-dev
To use it:
Edit your package.json to include the Jest environment:
{
"scripts": {
"test": "jest --env=jest-environment-happy-dom"
}
}
use electron runner can include all node and chrome env,
use this to replace jsdom
https://github.com/facebook-atom/jest-electron-runner
Here is an ugly version that kind of works. Some further notes on this:
express.js is configured to work as file server. Otherwise there would be issues with mime type or cross origin checking for the imported ES6 modules.
The class TreezElement is not directly imported but using the work around of creating an extra script tag
There are issues with instance methods regarding the code coverage. It does not seem to be possible to directly call the constructor of TreezElement (inherits from HTMLElement, => illegal constructor). An instance of the element class can only be created with document.createElement(...) in puppeteer. Therefore, all the instance methods cannot be tested in Jest but only static methods. The instance methods and properties can be tested in puppeteer. However, the code coverage of jest does not consider the code coverage of puppeteer.
The created element of type TreezElement can be returned in form of an ElementHandle. Accessing the properties and methods of the element instance is quite cumbersome (see example below). As an alternative to the handle approach, the page.$eval method can be applied:
var id = await page.$eval('#custom-element', element=> element.id);
index.html
<!doctype html>
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<div id="root"></div>
</body>
</html>
treezElement.test.js
import TreezElement from '../../src/components/treezElement.js';
import puppeteer from 'puppeteer';
import express from 'express';
describe('Construction', ()=>{
let port = 4444;
const index = Math.max(process.argv.indexOf('--port'), process.argv.indexOf('-p'))
if (index !== -1) {
port = +process.argv[index + 1] || port;
}
var elementHandle;
beforeAll(async () => {
const fileServer = await express()
.use(express.static('.'))
.listen(port);
var browser = await puppeteer.launch({
headless: false,
slowMo: 80,
userDataDir: '.chrome',
args: ['--auto-open-devtools-for-tabs']
});
var pages = await browser.pages();
var page = pages[0];
await page.goto('http://localhost:'+port + '/test/index.html');
await page.evaluate(() => {
var script = document.createElement('script');
script.type='module';
script.innerHTML="import TreezElement from '../src/components/treezElement.js';\n" +
"window.customElements.define('treez-element', TreezElement);\n" +
"var element = document.createElement('treez-element');\n" +
"element.id='custom-element';\n" +
"document.body.appendChild(element);";
document.head.appendChild(script);
});
elementHandle = await page.evaluateHandle(() => {
return document.getElementById('custom-element');
});
});
it('id', async ()=>{
var idHandle = await elementHandle.getProperty('id');
var id = await idHandle.jsonValue();
expect(id).toBe('custom-element');
});
afterAll(() => {
browser.close();
});
});
Another (limited) approach is to use Object.create as a work around to create an instance of the custom web component, without using window.customElements.define and document.createElement(..) :
import TreezElement from '../../src/components/treezElement.js';
var customElement = Object.create(TreezElement.prototype);
This way the instance methods can be tested directly in jest and the tests are included in the code coverage, too. (Also coverage issues of my other answer regarding puppeteer.)
A major disadvantage is that only the methods can be accessed, not the properties. If I try to use customElement.customProperty I get : TypeError: Illegal invocation.
This is caused by the check !module.exports.is(this) in Element.js:
Element.prototype.getAttribute = function getAttribute(qualifiedName) {
if (!this || !module.exports.is(this)) {
throw new TypeError("Illegal invocation");
}
...
Element.prototype.setAttribute = function setAttribute(qualifiedName,value){
if (!this || !module.exports.is(this)) {
throw new TypeError("Illegal invocation");
}
Another disadvantage of Object.create is that the constructor code is not called and not included in the test coverage.
If the command window.customElements.define(..) is directly included in a class file that we would like to import (e.g. treezElement.js) ... the customElements property needs to be mocked before including the import:
customElementsMock.js:
export default class CustomElementsMock{} //dummy export
//following command mocks the customElements feature to be able
//to import custom elements in jest tests
window.customElements = {
define: (elementName, elementClass)=>{
console.log('Mocked customElements.define(..) for custom element "' + elementName + '"');
}
};
usage in treezElement.test.js:
import CustomElementsMock from '../customElementsMock.js';
import TreezElement from '../../src/components/treezElement.js';
var customElement = Object.create(TreezElement.prototype);
//...
(I also tried to put the mock code directly at the beginning of treezElement.test.js but all the imports are executed prior to the script doing the import. That is why I had to put the mocking code in an extra file.)
I'm writing unit test for for vue cli 3 using Mocha and chai. I have tried mocking localstorage. but still getting this error - 'localStorage is not defined'. Can anyone please help me here?
My code is like this -
import { expect, assert } from 'chai';
import { shallowMount } from '#vue/test-utils';
import LoginComponent from '#/views/LoginComponent.vue';
import Constants from '#/constants';
declare var global: any;
let wrapper;
let componentInstance: any;
let authData;
var mockLocalStorage = {
getItem(key: any) {
if (key === 'access_token') { return '/* a token object */'; }
return 'null';
}
};
describe('LoginComponent.vue', () => {
beforeEach(() => {
global.window = { localStorage: mockLocalStorage };
authData = JSON.stringify(Constants.AUTH_DATA);
wrapper = shallowMount(AliUMSLoginComponent, {
propsData: { authData }
});
componentInstance = wrapper.vm;
});
it('has a created hook', () => {
assert.isNotNull(componentInstance.authData);
});
});
For anyone else who might stumble upon this question - the following worked for me:
1) Create a setup.js file in your unit test folder and add the following code:
require('jsdom-global')();
global.localStorage = window.localStorage;
After fixing the "localStorage is undefined" error, you might experience additional errors (like I did). In the end the following code snippet fixed everything:
require('jsdom-global')(undefined, { url: 'https://localhost' });
global.localStorage = window.localStorage;
global.sessionStorage = window.sessionStorage;
window.Date = Date;
... You can find more info on this here: vuejs/vue-cli/issues/2128 and here: vuejs/vue-test-utils/issues/936
2) Update the test script in your package.json file to load the setup file you just created:
"test:unit": "vue-cli-service test:unit --require tests/unit/setup.js"
I got your solution to work however when trying to grep for one file to run, it runs all files.
Is there a better way to include this maybe with an include at the top of the file? An include usually has a method that returns something. hmmmm how to do this?
Is this the correct syntax for the package.json file:
"test:unit-filter": "vue-cli-service test:unit --require tests/unit/helpers/setup.js --watch --grep"
I am testing a component which dynamically imports the child components. Here a screenshot of that section
Inside Parent.vue
Error
It works fine for normal imports but not with dynamic async import. Can anyone help on how configure Jest to support async component imports?
If problem is still relevant (I didn't found anydirect answer) try to 'stub' components which should be imported.
Component
<template>
<div>
<dynamic-imported-component-one id="componentOne"></dynamic-imported-component-one>
<dynamic-imported-component-two id="componentTwo"></dynamic-imported-component-two>
</div>
</template>
<script>
const ComponentOne = resolve => import(/* webpackChunkName: "views/view-ComponentOne-vue" */ '../Components/ComponentOne.vue');
const ComponentTwo = resolve => import(/* webpackChunkName: "views/view-ComponentTwo-vue" */ '../Components/ComponentTwo.vue');
export default {
components: {
'dynamicImportedComponentOne': ComponentOne,
'dynamicImportedComponentTwo': ComponentTwo }
}
</script>
Test:
describe('SomeComponent.vue', () => {
const stubs = {
dynamicImportedComponentOne: '<h3>Stubbed component one</h3>',
dynamicImportedComponentTwo: '<h3>Stubbed component one</h3>'
}
it('test for SomeComponent', () => {
const wrapper = shallowMount(SomeComponent, { stubs });
expect(wrapper.find('#componentOne').exists()).toBeTruthy();
expect(wrapper.find('#componentTwo').exists()).toBeTruthy();
});
});
You can't test the ComponentOne/ComponentTwo content, but it should be anyway done in separate tests.
Did you try using "dynamic-import-node" in you .babelrc ? It seemed to fix dynamic import of child components in a mounted parent for me. I got the pointer from https://github.com/enzymejs/enzyme/issues/1460#issuecomment-355193587
I have a text input and i'm listening for the changes.
mycomponent.ts
ngOnInit() {
this.searchInput = new Control();
this.searchInput.valueChanges
.distinctUntilChanged()
.subscribe(newValue => this.search(newValue))
}
search(query) {
// do something to search
}
mycomponent.html
<search-box>
<input type="text" [ngFormControl]="searchInput" >
</search-box>
Running the application everything works fine, but i want to unit-test it.
So here's what i tried
mycomponent.spec.ts
beforeEach(done => {
createComponent().then(fix => {
cmpFixture = fix
mockResponse()
instance = cmpFixture.componentInstance
cmpFixture.detectChanges();
done();
})
})
describe('on searching on the list', () => {
let compiled, input
beforeEach(() => {
cmpFixture.detectChanges();
compiled = cmpFixture.debugElement.nativeElement;
spyOn(instance, 'search').and.callThrough()
input = compiled.querySelector('search-box > input')
input.value = 'fake-search-query'
cmpFixture.detectChanges();
})
it('should call the .search() method', () => {
expect(instance.search).toHaveBeenCalled()
})
})
Test fails as the .search() method is not called.
I guess i have to set the value in another way to have the test realize of the change but i really don't know how.
Anyone has ideas?
It might be a little bit late, but it seems that your code is not dispatching input event after setting input element value:
// ...
input.value = 'fake-search-query';
input.dispatchEvent(new Event('input'));
cmpFixture.detectChanges();
// ...
Updating input html field from within an Angular 2 test
Triggering the value change of FormControl is as simple as:
cmpFixture.debugElement.componentInstance.searchInput.setValue(newValue);
Custom component with #input, subscriptions, two way data binding
If you got a custom component you would need further changes in your application to be able to successfully unit test your application
have a look at the gist here this will give you some idea
https://gist.github.com/AikoPath/050ad0ffb91d628d4b10ef81736af386/raw/846c7bcfc54be8cce78eba8d12015bf749b91eee/#ViewChild(ComponentUnderTestComponent).js
More over complete reading over here carefully otherwise you can easily get confused again -
https://betterprogramming.pub/testing-angular-components-with-input-3bd6c07cfaf6
I am using Mocha, Chai, Karma, Sinon, Webpack for Unit tests.
I followed this link to configure my testing environment for React-Redux Code.
How to implement testing + code coverage on React with Karma, Babel, and Webpack
I can successfully test my action and reducers javascript code, but when it comes to testing my components it always throw some error.
import React from 'react';
import TestUtils from 'react/lib/ReactTestUtils'; //I like using the Test Utils, but you can just use the DOM API instead.
import chai from 'chai';
// import sinon from 'sinon';
import spies from 'chai-spies';
chai.use(spies);
let should = chai.should()
, expect = chai.expect;
import { PhoneVerification } from '../PhoneVerification';
let fakeStore = {
'isFetching': false,
'usernameSettings': {
'errors': {},
'username': 'sahil',
'isEditable': false
},
'emailSettings': {
'email': 'test#test.com',
'isEmailVerified': false,
'isEditable': false
},
'passwordSettings': {
'errors': {},
'password': 'showsomestarz',
'isEditable': false
},
'phoneSettings': {
'isEditable': false,
'errors': {},
'otp': null,
'isOTPSent': false,
'isOTPReSent': false,
'isShowMissedCallNumber': false,
'isShowMissedCallVerificationLink': false,
'missedCallNumber': null,
'timeLeftToVerify': null,
'_verifiedNumber': null,
'timers': [],
'phone': '',
'isPhoneVerified': false
}
}
function setup () {
console.log(PhoneVerification);
// PhoneVerification.componentDidMount = chai.spy();
let output = TestUtils.renderIntoDocument(<PhoneVerification {...fakeStore}/>);
return {
output
}
}
describe('PhoneVerificationComponent', () => {
it('should render properly', (done) => {
const { output } = setup();
expect(PhoneVerification.prototype.componentDidMount).to.have.been.called;
done();
})
});
This following error comes up with above code.
FAILED TESTS:
PhoneVerificationComponent
✖ should render properly
Chrome 48.0.2564 (Mac OS X 10.11.3)
Error: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined.
Tried switching from sinon spies to chai-spies.
How should I unit test my React-Redux Connected Components(Smart Components)?
A prettier way to do this, is to export both your plain component, and the component wrapped in connect. The named export would be the component, the default is the wrapped component:
export class Sample extends Component {
render() {
let { verification } = this.props;
return (
<h3>This is my awesome component.</h3>
);
}
}
const select = (state) => {
return {
verification: state.verification
}
}
export default connect(select)(Sample);
In this way you can import normally in your app, but when it comes to testing you can import your named export using import { Sample } from 'component'.
The problem with the accepted answer is that we are exporting something unnecessarily just to be able to test it. And exporting a class just to test it is not a good idea in my opinion.
Here is a neater solution without the need of exporting anything but the connected component:
If you are using jest, you can mock connect method to return three things:
mapStateToProps
mapDispatchToProps
ReactComponent
Doing so is pretty simple. There are 2 ways: Inline mocks or global mocks.
1. Using inline mock
Add the following snippet before the test's describe function.
jest.mock('react-redux', () => {
return {
connect: (mapStateToProps, mapDispatchToProps) => (ReactComponent) => ({
mapStateToProps,
mapDispatchToProps,
ReactComponent
}),
Provider: ({ children }) => children
}
})
2. Using file mock
Create a file __mocks__/react-redux.js in the root (where package.json is located)
Add the following snippet in the file.
module.exports = {
connect: (mapStateToProps, mapDispatchToProps) => (ReactComponent) => ({
mapStateToProps,
mapDispatchToProps,
ReactComponent,
}),
Provider: ({children}) => children
};
After mocking, you would be able to access all the above three using Container.mapStateToProps,Container.mapDispatchToProps and Container.ReactComponent.
Container can be imported by simply doing
import Container from '<path>/<fileName>.container.js'
Hope it helps.
Note that if you use file mock. The mocked file will be used globally for all the test cases(unless you do jest.unmock('react-redux')) before the test case.
Edit: I have written a detailed blog explaining the above in detail:
http://rahulgaba.com/front-end/2018/10/19/unit-testing-redux-containers-the-better-way-using-jest.html
You can test your connected component and I think you should do so. You may want to test the unconnected component first, but I suggest that you will not have complete test coverage without also testing the connected component.
Below is an untested extract of what I do with Redux and Enzyme. The central idea is to use Provider to connect the state in test to the connected component in test.
import { Provider } from 'react-redux';
import configureMockStore from 'redux-mock-store';
import SongForm from '../SongForm'; // import the CONNECTED component
// Use the same middlewares you use with Redux's applyMiddleware
const mockStore = configureMockStore([ /* middlewares */ ]);
// Setup the entire state, not just the part Redux passes to the connected component.
const mockStoreInitialized = mockStore({
songs: {
songsList: {
songs: {
songTags: { /* ... */ }
}
}
}
});
const nullFcn1 = () => null;
const nullFcn2 = () => null;
const nullFcn3 = () => null;
const wrapper = mount( // enzyme
<Provider store={store}>
<SongForm
screen="add"
disabled={false}
handleFormSubmit={nullFcn1}
handleModifySong={nullFcn2}
handleDeleteSong={nullFcn3}
/>
</Provider>
);
const formPropsFromReduxForm = wrapper.find(SongForm).props(); // enzyme
expect(
formPropsFromReduxForm
).to.be.deep.equal({
screen: 'add',
songTags: initialSongTags,
disabled: false,
handleFormSubmit: nullFcn1,
handleModifySong: nullFcn2,
handleDeleteSong: nullFcn3,
});
===== ../SongForm.js
import React from 'react';
import { connect } from 'react-redux';
const SongForm = (/* object */ props) /* ReactNode */ => {
/* ... */
return (
<form onSubmit={handleSubmit(handleFormSubmit)}>
....
</form>
};
const mapStateToProps = (/* object */ state) /* object */ => ({
songTags: state.songs.songTags
});
const mapDispatchToProps = () /* object..function */ => ({ /* ... */ });
export default connect(mapStateToProps, mapDispatchToProps)(SongForm)
You may want to create a store with pure Redux. redux-mock-store is just a light-weight version of it meant for testing.
You may want to use react-addons-test-utils instead of airbnb's Enzyme.
I use airbnb's chai-enzyme to have React-aware expect options. It was not needed in this example.
redux-mock-store is an awesome tool to test redux connected components in react
const containerElement = shallow((<Provider store={store}><ContainerElement /></Provider>));
Create fake store and mount the component
You may refer to this article Testing redux store connected React Components using Jest and Enzyme | TDD | REACT | REACT NATIVE
Try creating 2 files, one with component itself, being not aware of any store or anything (PhoneVerification-component.js). Then second one (PhoneVerification.js), which you will use in your application and which only returns the first component subscribed to store via connect function, something like
import PhoneVerificationComponent from './PhoneVerification-component.js'
import {connect} from 'react-redux'
...
export default connect(mapStateToProps, mapDispatchToProps)(PhoneVerificationComponent)
Then you can test your "dumb" component by requiring PhoneVerification-component.js in your test and providing it with necessary mocked props. There is no point of testing already tested (connect decorator, mapStateToProps, mapDispatchToProps etc...)