How to nest Vue.nextTick when testing? - testing

I'm trying to test what happens in my app on two consecutive ticks. This is what I have so far (the tests fail in the karma devtools, but fail in the command line):
import { mount } from 'avoriaz';
import MyComponent from './MyComponent';
describe('testing', function() {
it('should do something', (done) => {
const wrapper = mount(MyComponent, { store });
wrapper.vm.changeData();
Vue.nextTick(() => {
expect(wrapper.vm.something).to.eql(somethingElse);
wrapper.vm.changeData();
Vue.nextTick(() => {
expect(wrapper.vm.something2).to.eql(somethingElse2);
done();
});
done();
});
});
});
I also tried using then() and catch(), but karma still thinks my failing tests are passing.
Should I only have one done() call? I'm not really sure what this callback is doing.

As indicated here, there is an even better solution, which prevents Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.:
it('should do something', (done) => {
const wrapper = mount(MyComponent, { store });
wrapper.vm.changeData();
Vue.nextTick(() => {
expect(wrapper.vm.something).to.eql(somethingElse);
wrapper.vm.changeData();
Vue.nextTick().then(() => {
expect(wrapper.vm.something2).to.eql(somethingElse2);
}).then(done, done);
});
});
I'd like to also use the async/await version, but I wasn't able to get it to work.

Related

Calling methods inside beforeRouteEnter NProgress

I am trying to call an API before navigating to the route. The problem is that if I try to call axios call inside beforeRouteEnter it is working fine for example:
{
beforeRouteEnter(routeTo, routeFrom, next) {
NProgress.start()
axios.get('https://jsonplaceholder.typicode.com/posts').then((res) => {
next((vm) => {
vm.data = res.data
})
NProgress.done()
})
},
}
But when I try to call an API from methods it's navigating to the route before resolving an API and also NProgress bar is also completing before resolving a call.
{
beforeRouteEnter(routeTo, routeFrom, next) {
NProgress.start()
next((vm) => {
vm.index()
NProgress.done()
})
},
methods: {
index() {
axios
.get('https://jsonplaceholder.typicode.com/posts')
.then((res) => {
console.log(res.data)
})
.catch((error) => {
console.log(error)
})
},
},
}
Can anyone guide me what may be wrong?
In your first example, you set the progress bar, then you call the API with Axios and with .then you chain a function after the call. This means the function will wait until the promise is resolved or rejected, before continuing. Only when the axios call is finished successfully, the next function is executed in which you set the data and stop the progress bar. You also should use .catch for if the promises rejects.
Now in your second example, you do not use promises in beforeRouteEnter. Which basically means that all lines are executed immediately. So you call vm.index() and without waiting for the axios call to finish the next line, NProgress.done() will be executed. Although there are several ways to solve this my preference is use async/await, which is just a cleaner way to use promisses and chaining.
In your case I think this would work:
beforeRouteEnter(routeTo, routeFrom, next) {
NProgress.start();
await vm.index();
NProgress.done();
next();
});
}
And the method:
methods: {
async index () {
try {
const response = await axios.get('https://jsonplaceholder.typicode.com/posts');
console.log(response);
} catch (error) {
console.log(error);
}
}
}
Since this is only a part of your component I cannot test it, but I think you get the idea.

Vitest LitElement events

I have a storybook project where i am using Vite and LitElement components.
To test the components i thought i would use the Vitest library.
But i can't really test my components, it is like if the components aren't initialized / mounted / working (but they work fine in the stories., so i think the problem is with the testing).
I have a breadcrumb component, which dispatches a custom event on the connectedCallback function. On my story i can listen to this event, so i know it is being dispatched.
But i can seem to test it.
What i have:
on the breadcrumb component, inside the connectedCallback function
this.dispatchEvent(new Event('abc-breadcrumb-connected'));
on my breadcrumb.test.ts file:
import type { IWindow } from 'happy-dom';
import { expect, describe, it, beforeEach, vi } from 'vitest';
import '../abc-breadcrumb';
import { AbcBreadcrumb } from "../abc-breadcrumb";
declare global {
interface Window extends IWindow {}
}
describe('Abc breadcrumb', async () => {
it('Dispatches connected event', async () => {
const mockConnectedCallback = vi.fn(() => true);
window.addEventListener('abc-breadcrumb-connected', () => {
console.log('GOT THE EVENT');
mockConnectedCallback()
});
document.body.innerHTML = `
<abc-breadcrumb role="nav" aria-label="Breadcrumb" class="breadcrumb" ismobile="">
...
</abc-breadcrumb>
`;
await window.happyDOM.whenAsyncComplete();
await new Promise(resolve => setTimeout(resolve, 0));
expect(mockConnectedCallback).toHaveBeenCalled();
})
});
0n my vite.config.ts i have:
export default defineConfig({
test: {
globals: true,
environment: 'happy-dom',
},
...
})
the error i get:
AssertionError: expected "spy" to be called at least once
I have no idea why it isn't working an would be really happy to get some help.
Thanks!
At first look, using await new Promise(resolve => setTimeout(resolve, 0)); seems like the kind of thing I was unsuccessfully relying on myself to ensure enough ticks had passed for various operations to complete. This often worked in my local browser but failed in CI or resulted in flaky tests.
Why not set up the promise such that the event listener calls resolve() or possibly even mockConnectedCallback(). Then you can be certain the event isn't firing as opposed to only not having been fired when setTimeout resolves.
const mockConnectedCallback = vi.fn(() => true);
let connectedResolve;
const connectedPromise = new Promise(r => connectedResolve = r);
window.addEventListener('abc-breadcrumb-connected', () => {
console.log('GOT THE EVENT');
connectedResolve();
mockConnectedCallback();
});
document.body.innerHTML = `
<abc-breadcrumb role="nav" aria-label="Breadcrumb" class="breadcrumb" ismobile="">
...
</abc-breadcrumb>
`;
await window.happyDOM.whenAsyncComplete();
await connectedPromise;
expect(mockConnectedCallback).toHaveBeenCalled();
It makes the expect() a little redundant given that it won't be reached until the awaited promise resolves, but I think awaiting an explicit resolution makes things easier to reason about and doesn't hard-code various assumptions about microtask queues and things into the test code, which more often than not have come back to bite me later.

Overriding Cypress' before and after methods

We are using Cypress.io to build our automation suite. We have a requirement to seed our database before every test and to clear the data afterward. This could be done like below.
describe('Our test suite', function() {
before(function () {
//loadDbSeed is a custom command that will load the seed file based on the spec file
seed = cy.loadDbSeed()
cy.task('seed:db', seed)
})
it('should be true', function() {
//Some test with some action followed by an assertion
cy.visit('/some-page')
cy.get('[data-cy="identifier"]')
.click()
expect(true).to.equal(true)
})
after(function () {
// clearDb is a custom command that will clear out the DB.
// We are still debating if we must clear the DB after the tests.
// But we might still need to do some common actions for the entire suite after
cy.clearDb()
})
})
The problem we see is that the same before and after operations will be required for all our test suites. So we would like to override these methods so that our tests are something like this.
describe('Our test suite', function() {
before(function () {
// DB seeding is done automatically
// Write only custom before steps required for this test
})
it('should be true', function() {
//Some test with some action followed by an assertion
cy.visit('/some-page')
cy.get('[data-cy="identifier"]')
.click()
expect(true).to.equal(true)
})
after(function () {
// DB clearing is done automatically
// Write only custom after steps required for this test
})
})
How do we achieve this? I have been digging around in the Cypress code and haven't found anything obvious.
If you look at the Cypress docs, using after isn't recommended - Cypress Docs. I'd caution against setting data globally, will you really need it for every test? If you need to enter data on a per-test basis at some point, will that conflict with this global data? You could do something like this on a per test basis:
describe('Our test suite', function() {
beforeEach(function () {
cy.then(async () => {
await MyDatabaseService.resetdata()
await MyDatabaseService.createSomeData()
});
});
it('should be true', function() {
//Some test with some action followed by an assertion
})
})
I've also had to nest some tests as follows when specific tests needed specific data (sorry if some of the formatting here is a bit out, hopefully it'll make sense!):
describe('Our test suite', function() {
beforeEach(function () {
cy.then(async () => {
await MyDatabaseService.resetdata()
await MyDatabaseService.createSomeData()
});
});
it('should be true', function() {
//Some test with some action followed by an assertion
});
describe('These tests need more data, this is a nested describe', function () {
before(function () {
cy.then(async () => {
await MyDatabaseService.addSomeMoreData()
});
it('this test uses the extra data', function () {
// Do some funky tests here
});
});
});
})
For the second tests above, the test will run all three database actions.
Upshot is, if you clear data before you run your tests then it makes things much clearer.
I hope that helps. I'm new to Cypress myself and it can be hard to drop that (bad?) habits we've used for some time in Selenium!

How Test with Jest a function in the method "mounted" VueJS

I would to try call a function already mocked. I use vueJS for the frond and Jest as unit test. Below a example of my code. My purpose is to test the call of « anotherFunction". The first test is succeed , not the second.Thanks for help or suggestion
code vueJS:
mounted() {
this.myfunction();
}
methods: {
myfunction() {
this.anotherFunction();
}
}
Jest code:
describe('Home.vue', () => {
let wrapper = null;
const options = {
mocks: {
$t: () => 'some specific text',
},
methods: {
myFunction: jest.fn(),
},
};
it('Should renders Home Component', () => {
// Given
wrapper = shallowMount(Home, options);
// Then
expect(wrapper).toBeTruthy();
});
it('Should call anotherFunction', async (done) => {
// Given
wrapper.vm.anotherFunction = jest.fn().mockResolvedValue([]);
// When
await wrapper.vm.myFunction();
// THIS THE PROBLEM, myFunction is mocked and I can't call the function 'anotherFunction' inside...
// Then
// expect(wrapper.vm.anotherFunction).toHaveBeenCalled();
});
});
I was finding a good way to help you if this test case. So, I thought in something like the chuck code below:
import { mount } from '#vue/test-utils';
describe('Home', () => {
it('method calls test case', () => {
const anotherMethodMock = jest.fn();
wrapper = mount(Home, {
methods: {
anotherMethod: anotherMethodMock
}
});
expect(anotherMethodMock).toHaveBeenCalled();
});
});
But, the Jest threw the following exception:
[vue-test-utils]: overwriting methods via the methods property is deprecated and will be removed in the next major version. There is no clear migration path for themethods property - Vue does not support arbitrarily replacement of methods, nor should VTU. To stub a complex m ethod extract it from the component and test it in isolation. Otherwise, the suggestion is to rethink those tests.
I had the following insight, maybe, in this case, should be better to test the side effect of this anotherMethod calling. What does it change? Is something being shown to the user?
I believe that here we have started from the wrong concept.
I hope that this tip could be useful :)
As suggested by #Vinícius Alonso, We should avoid using methods and setMethods in our test cases because of it's deprecation. But you can still test the mounted lifecycle by mocking the functions that are being called during mount. So you can do something similar to below snippet.
describe('Mounted Lifecycle', () => {
const mockMethodOne = jest.spyOn(MyComponent.methods, 'methodOne');
const mockMethodTwo = jest.spyOn(MyComponent.methods, 'methodTwo');
it('Validate data and function call during mount', () => {
const wrapper = shallowMount(MyComponent);
expect(mockMethodOne).toHaveBeenCalled();
expect(mockMethodTwo).toHaveBeenCalled();
})
})
Do mount/shallowMount inside it only rather putting it outside of it as it was not working in my case. You can checkout more details on it if you want.

Unit Test Rxjs 5

I am trying to write a test using mocha and chai for my observable methods that makes a call to a server and returns some json data. However, when I run the test I get the following error:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
Even when I overwrite the default timeout time, I still get the above error. What am I doing wrong ?
describe("some test", () => {
let someClass: SomeClass;
before(() => {
someClass = new SomeClass();
});
;
it("should meet some condition", done => {
let getData = someClass.getData('query')
getData.subscribe(json => {
json.success.should.equal(true);
done();
},
done
);
});
});
I found a solution, I call done() in the before hook and the set timeout on each it() function.
describe("some test", () => {
let someClass: SomeClass;
before((done) => {
someClass = new SomeClass();
done();
});
;
it("should meet some condition", done => {
let getData = someClass.getData('query')
getData.subscribe(json => {
json.success.should.equal(true);
done();
},
done
);
}).timeout(10000);
});