Angular 2 + Jasmine - Test whether an element is visible - unit-testing

I'm testing a web app made using Angular (2+), I'm using Jasmine + Karma as testing environment.
I've searched a lot but I'm not able to test whether an element is visible or not, I thought I'd find a canned matcher or some utility method from Angular, but I didn't.
I tried using classList property of HTMLElement, testing for :visible, but that's not working.
I feel I'm missing something basic, since it should be something basic to achieve.
So, in the example below, how I can test that the div with id header-menu-dropdown-button is visible ?
Here's the test method I'm struggling with:
Template
<div id="header-menu-dropdown-button" class="dropdown-closing-level" [hidden]="!showUserMenu" (click)="showMenu($event)"></div>
<ul [hidden]="!showUserMenu" class="dropdown-menu" aria-labelledby="dropdown">
<li class="dropdown-item">Account</li>
<li class="dropdown-item">Logout</li>
</ul>
Test
beforeEach(async(() => {
TestBed.configureTestingModule({
imports: [RouterTestingModule, TranslationsModule],
declarations: [ AppHeaderComponent ], // declare the test component
})
}));
beforeEach(() => {
fixture = TestBed.createComponent(AppHeaderComponent);
comp = fixture.componentInstance;
menuDropDownButtonDe = fixture.debugElement.query(By.css('#header-menu-dropdown-button'));
menuDropDownButtonEl = menuDropDownButtonDe.nativeElement;
});
it('menu should be closed by default', () => {
//Here I want to check the visibility of the menuDropDownButtonEl element
expect(menuDropDownButtonEl.classList.contains(":visible")).toBe(false); // <-- not working
});
NOTE: showMenu method simply toggles the showUserMenu boolean value.

I unit test it by checking for the existence of the hidden attribute.
expect(menuDropDownButtonEl.hasAttribute('hidden')).toEqual(true);

Related

Mocking BsModalRef for Unit Testing

I am using the BsModalRef for showing modals and sending data using the content property. So we have some like this :
this.followerService.getFollowers(this.bsModalRef.content.channelId).subscribe((followers) => {
this.followerList = followers;
this.followerList.forEach((follower) => {
follower.avatarLink = this.setUserImage(follower.userId);
this.followerEmails.push(follower.email);
});
});
We are setting the channelId in content of bsModalRef (this.bsModalRef.content.channelId). It is working fine. Now i am writing a unit test for this. Problem is i am not able to mock it. I have tried overriding, spy etc but nothing seems to work. I am using the approach mentioned in this link. One alternative is to use TestBed but i am not much aware of its use. Can anyone please help me finding any approach by which this can be achieved ?
I recently had to do something similar and Mocking the method call worked. The tricky part is injecting the BsModalService in both the test suite and the component.
describe('MyFollowerService', () => {
configureTestSuite(() => {
TestBed.configureTestingModule({
imports: [...],
declarations: [...],
providers: [...]
}).compileComponents();
});
// inject the service
beforeEach(() => {
bsModalService = getTestBed().get(BsModalService);
}
it('test', () => {
// Mock the method call
bsModalService.show = (): BsModalRef => {
return {hide: null, content: {channelId: 123}, setClass: null};
};
// Do the test that calls the modal
});
});
As long as you're calling bsModal as follows this approach will work
let bsModalRef = this.modalService.show(MyChannelModalComponent));
Finally, here are some links that have more indepth coverage about setting up the tests with TestBed.
https://chariotsolutions.com/blog/post/testing-angular-2-0-x-services-http-jasmine-karma/
http://angulartestingquickstart.com/
https://angular.io/guide/testing

How to Test a Global Event Bus With Vue Test Utils?

I am trying to learn how to test events emitted through a global Event Bus. Here's the code with some comments in the places I don't know what to do.
// EvtBus.js
import Vue from 'vue';
export const EvtBus = new Vue();
<!-- CouponCode.vue -->
<template>
<div>
<input
class="coupon-code"
type="text"
v-model="code"
#input="validate">
<p v-if="valid">
Coupon Redeemed: {{ message }}
</p>
</div>
</template>
<script>
import { EvtBus } from '../EvtBus.js';
export default {
data () {
return {
code: '',
valid: false,
coupons: [
{
code: '50OFF',
discount: 50,
message: '50% Off!'
},
{
code: 'FREE',
discount: 100,
message: 'Entirely Free!'
}
]
};
},
created () {
EvtBus.$on('coupon-applied', () => {
//console.info('had a coupon applied event on component');
});
},
methods: {
validate () {
// Extract the coupon codes into an array and check if that array
// includes the typed in coupon code.
this.valid = this.coupons.map(coupon => coupon.code).includes(this.code);
if (this.valid) {
this.$emit('applied');
// I NEVER see this on the coupon-code.spec.js
EvtBus.$emit('coupon-applied');
}
}
},
computed: {
message () {
return this.coupons.find(coupon => coupon.code === this.code).message;
}
}
}
</script>
// tests/coupon-code.spec.js
import expect from 'expect';
import { mount } from '#vue/test-utils';
import CouponCode from '../src/components/CouponCode.vue';
import { EvtBus } from '../src/EvtBus.js';
describe('Reminders', () => {
let wrp;
beforeEach(() => {
wrp = mount(CouponCode);
});
it('broadcasts the percentage discount when a valid coupon code is applied', () => {
let code = wrp.find('input.coupon-code');
code.element.value = '50OFF';
code.trigger('input');
console.log(wrp.emitted('applied'));
//
// I NEVER see this on the outpout.
// How can I test it through a global event bus rather than
// an event emitted from the component instance?
//
EvtBus.$on('coupon-applied', () => {
console.log('coupon was applied through event bus');
});
// Passes, but not using EvtBus instance.
expect(wrp.emitted('applied')).toBeTruthy;
});
});
So, my doubt is how to test that the global event bus is emitting and listening to events inside components that use that event bus.
So, is it possible to test the global Event Bus using Vue Test Utils or I should use another approach?
If component is using global EventBus, eg that's imported outside of given component and assigned to window.EventBus, then it's possible to use global Vue instance to redirect $on or $emit events to wrapper's vm instance. That way you can proceed writing tests as if component is emitting via this.$emit instead of EventBus.$emit:
it('clicking "Settings" button emits "openSettings"', () => {
global.EventBus = new Vue();
global.EventBus.$on('openSettings', (data) => {
wrapper.vm.$emit('openSettings', data);
});
// component emits `EventBus.$emit('openSettings')`
expect(wrapper.emitted('openSettings')).toBeTruthy(); // pass
});
Well,
EvtBus.$on('coupon-applied', () => {
console.log('coupon was applied through event bus');
});
This code in your spec file won't be called because the mounted wrp component is not using the same EvtBus you are importing in your spec file above.
What you require to test this is an npm package named inject-loader so that you can provide your own implementation(stub) of the EvtBus dependency of your coupon code component.
Somewhat like this
const couponCodeInjector = require('!!vue-loader?inject!src/views/CouponCode');
const stubbedModules = {
'../EvtBus.js': {
$on : sandbox.spy((evtName, cb) => cb());
}
};
const couponCode = couponCodeInjector(stubbedModules);
and then in your unit test you can assert whether the stubbedModules['../EvtBus.js'].$on has been called or not when code.trigger('input');
PS: I haven't used vue-test-utils. So I don't know exactly how to the stubbing with this npm package.
But the main thing you need to do is to find a way to stub your EvtBus dependency in the CouponCode component in such a way that you can apply a spy on it and check whether that spy has been called or not.
Unit tests should focus on testing a single component in isolation. In this case, you want to test if the event is emitted, since that is the job of CouponCode.vue. Remember, unit tests should focus on testing the smallest units of code, and only test one thing at a time. In this case, we care that the event is emitted -- EventBus.test.js is where we test what happens when the event is emitted.
Noe that toBeTruthy is a function - you need (). expect(wrp.emitted('applied')).toBeTruthy is actually not passing, since you need () - at the moment, it is actually doing nothing -- no assertion is made.
What your assertion should look like is:
expect(wrp.emitted('applied')).toBeTruthy()
You can go one step further, and ensure it was only emitted once by doing something like expect(wrp.emitted().applied.length).toBe(1).
You then test InputBus in isolation, too. If you can post the code for that component, we can work through how to test it.
I worked on a big Vue app recently and contributed a lot to the main repo and documentation, so I'm happy to help out wherever I can.
Let me know if that helps or you need more guidance. If possible, post EventBus.vue as well.
I got the same issue with vue-test-utils and Jest. For me, createLocalVue() of vue-test-utils library fixed the issue. This function creates a local copy of Vue to use when mounting the component. Installing plugins on this copy of Vue prevents polluting the original Vue copy. (https://vue-test-utils.vuejs.org/api/options.html#localvue)
Adding this to your test file will fix the issue:
const EventBus = new Vue();
const GlobalPlugins = {
install(v) {
// Event bus
v.prototype.$bus = EventBus;
},
};
// create a local instance of the global bus
const localVue = createLocalVue();
localVue.use(GlobalPlugins);
jest.mock('#/main', () => ({
$emit: jest.fn(),
}));
Include this in code in your spec file at the very begining.
Note: '#/main' is the file from which you are importing Event Bus.

Child component's template does not change, when parent component method is called Angular 2 unit tests

This doesn't work for me. Please make the Plunkr below work.
describe("trying a test", () => {
beforeEach(() => {
TestBed.initTestEnvironment(BrowserDynamicTestingModule, platformBrowserDynamicTesting());
TestBed.configureTestingModule({
declarations: [myCmp, ChildCmp]
});
});
it("test should work", () => {
const fixture = TestBed.createComponent(myCmp);
const div = fixture.debugElement.children[0];
const childCmp = div.queryAll(By.directive(ChildCmp));
const divEl = div.queryAll(By.css('div'));
divEl[0].triggerEventHandler('click', <Event>{});
fixture.detectChanges();
expect(childCmp[0].nativeElement.textContent).toBe("updated value");
});
});
https://plnkr.co/edit/wWJMDi3ZFC6RTSvCw4HH?p=preview
This is no longer an issue for me. For the most part (with one exception I will outline below), both my parent components and child components get updated in my real app code, though I haven't updated the Plunkr.
I just use .and.callThrough() on the spyed on parent component method that is called, when something is clicked on the template. Rather than a simple spy.
I do have an issue with ngFor rendered child components not updating. This is my other question: Angular 2 unit testing: Make ngFor rendered, child components' templates change?

Jasmine - Unble to get DOM elements

I am testing an angularjs directive that manipulates the DOM.
I am trying to get the element in my Jasmine spec, so that I can test the functionality of the directive. However, when I use document.getElementsByClassName or TagName or ID, it doesn't return anything. Does anyone have ideas about this?
html = document.getElementsByClassName('analog');
console.dir(html);
If you create a test in headless browser/chrome etc., you could append a dummy object, for example JQuery node, then remove that node in afterEach.
E.g.
beforeEach(() => {
var mockHtml = $('<div class="form-group" style="position: absolute;left: -10000px;"><input class="testInput" id="some_input"></div>');
$('body').append(mockHtml);
});
afterEach(() => {
$('.form-group').remove();
});

React Test Utils - Spy not called when a simulated click is performed -

I'm trying to simulate a click on a dom element in a react component and assert that a spy is called based on this. Here's the relevant part of the test (using karma, mocha, chai, sinon but I'm fairly sure that's irrelevant here):
const selectSpy = sinon.spy();
const component = TestUtils.renderIntoDocument(<SomeComponent onSelect={selectSpy} />);
TestUtils.Simulate.click(TestUtils.scryRenderedDOMComponentsWithTag(component, 'li'));
expect(selectSpy.called).to.be.ok;
and here's the react component:
render() {
let { title , data, onSelect } = this.props;
console.log(this.props.onSelect); // This correctly logs out the spy
return (
<div>
<ul>{data.map((row, i) => {
return <li onClick={this.handle.bind(this,row)} key={i}>{row.title}</li>; })}
</ul>
</div>
)
}
handle(row) {
this.props.onSelect(row);
}
The test runs but the result is a failed test with the message "Expected false to be truthy". I can't see much wrong with the code - there are no errors and my spy is correctly passed.
Is there something else I need to be doing?
TestUtils.Simulate.click expects a DOM element, but scryRenderedDOMComponentsWithTag returns an array of DOM elements.
Try changing
TestUtils.Simulate.click(TestUtils.scryRenderedDOMComponentsWithTag(component, 'li'));
to
TestUtils.Simulate.click(TestUtils.scryRenderedDOMComponentsWithTag(component, 'li')[0]);