How should I test vue components when using Firebase? - javascript

I'm writing unit tests for a vue project that uses firebase. The tests are using vue-test-utils.
The thing is I'm having trouble trying to bypass the auth, and with every test I find myself doing something like this.
...
const login = async () => {
return firebase.auth().signInWithEmailAndPassword(email, pass).then(
res => {
return res
},
err => {
return new Error(err)
})
}
...
describe('some component', () => {
it('test something', async () => {
try {
await login()
...
} catch (e) {
...
}
})
it('test something else', async () => {
try {
await login()
...
} catch (e) {
...
}
})
})
My question is. What is the recommended way to test vue components that use firebase and how to avoid having to login for every test?
Hope I explained my question correctly!
I ended up doing this, as in my case it's enough to do it once.
...
beforeAll(() => {
return login()
})
describe('some component', ...

One approach is to use a beforeEach function in your test suite to get authenticated/check if authentication is still valid, simply:
beforeEach(() => {
try {
await login()
...
} catch (e) {
...
}
})
However, are you doing this logic directly in a vue component? You ideally don't want to make these kind of calls directly from your vue components. If you move that logic out of your component and into a service class (or go a step further and use vuex to manage your state etc..), then you can test the firebase logic separately from your component logic.

Related

mock a service with Jest

Trying to write a test to provide code coverage for the following code :
note : there are other functions in the service but just listing one for brevity.
export const service = {
getById: async (id) => {
const url = `/api/customers/${id}/names`
const {data} = await axios.get(url, axiosOptions);
return data;
}
I'm attempting to simply provide code coverage with this test:
note : I have attempted to use require instead of import but that does not seem to work.
import {service} from './requests';
it("mocks the getById function", () => {
service.getById = jest.fn();
expect(service.getById.mock).toBeTruthy();
}
This test passes however seems to provide no code coverage.
I've attempted to mock out the axios call but I seem to get nowhere as examples I've found of implementations are not working for me currently.
Does anyone have ideas and an example how I could provide code coverage for the service please?
Update : to sonEtLumiere's answer
jest.mock('./service', () => ({
getById: jest.fn().mockResolvedValue({ data : "hello"}),
}));
describe('test', () => {
it('mocks the service", async () => {
service.getById.mockResolvedValue({data: "hello});
const data = await service.getById(1);
expect(data).toEqual({data:"hello"});
})
})
Currently getting back error :
Cannot read properties of undefined (reading 'getById')
Any thoughts on why I'm getting this error?
To mock a service using Jest, you can use the jest.mock() function to create a mocked version of the service. For example:
jest.mock('path/to/service', () => ({
getById: jest.fn().mockResolvedValue({ /* mocked data */ }),
}));
Then, in your test file, you can import the mocked version of the service and use the mock property on the function to control its behavior. For example, you can use .mockResolvedValue to set the resolved value of the function, or use .mockRejectedValue to make the function throw an error.
import { service } from 'path/to/service';
describe('test', () => {
it('mocks the service', async () => {
service.getById.mockResolvedValue({ /* mocked data */ });
const data = await service.getById(1);
expect(data).toEqual({ /* mocked data */ });
});
});
I do agree with #Lin Du's comment, if you want to test service.getById, you should be mocking what the method depends on, in this case axios.get.
But following along with your question, the issue is that the named export in ./requests is an object containing the getById property which is the method you want to test. So jest.mock should look like:
jest.mock("./requests.js", () => ({
service: {
getById: jest.fn(),
},
}))
Then your test will pass as you expected:
it("mocks the getById function", async () => {
service.getById.mockResolvedValueOnce({ data: "hello" })
const data = await service.getById(1)
expect(data).toEqual({ data: "hello" })
})
But again, if you want to test a method and have proper coverage, what you need to mock is the method's dependency, not the method itself, e.g:
import { service } from "./requests"
import axios from "axios"
jest.mock("axios")
test("service.getById", async () => {
axios.get.mockResolvedValueOnce({ data: "hello" })
const result = await service.getById(1)
expect(result).toBe("hello")
})

How to globally createConnection() with TypeORM in unit tests?

I have a node.js application inside TypeORM's createConnection() body:
// index.ts
import { createConnection } from "typeorm";
createConnection().then(async connection => {
// express app code here
}).catch(error => console.log(error));
Now, I wanted to write unit test cases using jest and I wanted the connection to be available across the tests
// abc.test.ts
createConnection().then(async connection => {
describe('ABC controller tests', () => {
it('should test abc function1', async () => {
// test body does here
});
});
}).catch(error => console.log(error));
I have a few concerns:
This is my first time working with TypeORM, so I don't have any hands-on experience on it
It doesn't even work & throws SyntaxError: Cannot use import statement outside a module
It looks like a very ugly approach
I wanted the connection making code at only one place, not in every test file but there is no entry point for tests like the app has index.ts
How to globally createConnection() with TypeORM in unit tests?
You should use beforeEach and afterEach to set up your state/context/world. Something like:
describe('ABC controller tests', () => {
let connection: Connection
beforeEach(async () => {
connection = await createConnection()
})
it('should test abc function1', async () => {
connection.doSomething()
})
afterEach(async () => {
await connection.close()
})
})
You should be able to create
jest.setup.js (setupFilesAfterEnv)
// Promise<Connection>
global.connection = createConnection()
and then you can await the Promise to be resolved in your tests
abc.test.ts
describe('abc', () => {
beforeAll(async () => {
await global.connection
});
it('should be connected', () => {
// not sure if that property really exists
expect(global.connection).toHaveProperty('isConnected', true)
})
})

How to unit test promise rejection in React and Jest

I am trying to write a unit test for a react component. It's a fairly standard component which calls a promise-returning method and uses 'then' and 'catch' to handle the resolution. My test is trying to validate that it calls the correct method when the promise is rejected however despite following what i believe is a standard patttern, I cannot get jest to validate the call. I have listed the relevant files here and have also put up a github sample, which is linked at the bottom of the question. That sample is simply a new react app created using npx and the files below added in.
Here is my example component:
import React from 'react';
import api from '../api/ListApi';
class ListComponent extends React.Component {
constructor(props) {
super(props);
this.fetchListSuccess = this.fetchListSuccess.bind(this);
this.fetchListFailed = this.fetchListFailed.bind(this);
}
fetchList() {
api.getList()
.then(this.fetchListSuccess)
.catch(this.fetchListFailed);
}
fetchListSuccess(response) {
console.log({response});
};
fetchListFailed(error) {
console.log({error});
};
render() {
return(<div>Some content</div>);
};
}
export default ListComponent;
Here is the api class (note, the api doesnt exist if you run the app, its just here for example):
const getList = () => fetch("http://someApiWhichDoesNotExist/GetList");
export default { getList };
And here is the test case:
import ListComponent from './ListComponent';
import api from '../api//ListApi';
describe('ListComponent > fetchList() > When the call to getList fails', () => {
it('Should call fetchListFailed with the error', async () => {
expect.hasAssertions();
//Arrange
const error = { message: "some error" };
const errorResponse = () => Promise.reject(error);
const componentInstance = new ListComponent();
api.getList = jest.fn(() => errorResponse());
componentInstance.fetchListFailed = jest.fn(() => { });
//Act
componentInstance.fetchList();
//Assert
try {
await errorResponse;
} catch (er) {
expect(componentInstance.fetchListFailed).toHaveBeenCalledWith(error);
}
});
});
The problem is that the test is not executing the catch block, so, in this case, the expect.hasAssertions() is failing the test. Can anyone help me understand the catch block is not executing? Wrapping the await in the try block and asserting in the catch seems to be a standard pattern in the docs but I am fairly new to Js and React and am obviously doing something wrong.
Here is the sample project on GitHub. Any help would be greatly appreciated =)
In your console:
const errorResponse = () => Promise.reject();
await errorResponse;
//() => Promise.reject()
You're awaiting a function, not the result of the call to that function. You want to:
await errorResponse();
EDIT:
In addition to that, the rest of your test is confusing. I believe you actually want to test what happens when the fetchList method of your component is called, and it fails, I assume. So you need to call it in your test, and await it's response:
Update your component's fetchList method to return the promise.
await componentInstance.fetchList() instead of await errorResponse()
Because you catch the error in fetchList you'll never enter the catch or the try...catch so your final test should look like this:
Test:
//Arrange
const error = { message: "some error" };
const errorResponse = () => Promise.reject(error);
const componentInstance = new ListComponent();
api.getList = jest.fn(() => errorResponse());
componentInstance.fetchListFailed = jest.fn(() => { });
//Act
await componentInstance.fetchList();
expect(componentInstance.fetchListFailed).toHaveBeenCalledWith(error);
Component:
fetchList() {
return api.getList()
.then(this.fetchListSuccess)
.catch(this.fetchListFailed);
}
My two cents, with my own case in a React native app:
In my component I have:
const handleRedirect = React.useCallback(() => {
client.clearStore()
.then(navigation.push('SomeScreen'))
.catch(e => logger.error('error', e));
}, []);
My test is this one, where I want to test if the promise is rejected:
it('should throw an exception on clearStore rejected', async () => {
const client = {
clearStore: jest.fn()
};
const error = new Error('clearStore failed');
client.clearStore.mockReturnValue(Promise.reject(error));
expect.assertions(1);
await expect(client.clearStore())
.rejects.toEqual(Error('clearStore failed'));
});

JestJS: Async test isn't stopped

I got two problems with this jest test:
Is it possible to define the Content collection only once instead of doing that inside of the test?
I do get this error:
Jest did not exit one second after the test run has completed.
This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with --detectOpenHandles to troubleshoot this issue.
I don't see why my async code weren't stopped...
import resolvers from 'resolvers/'
import Db from 'lib/db'
const db = new Db()
describe('Resolver', () => {
let token
beforeAll(async () => {
await db.connect()
})
beforeEach(async () => {
token = 'string'
await db.dropDB()
})
afterAll(async () => {
await db.connection.close()
})
describe('articleGetContent()', () => {
test('should return dataset', async () => {
// SETUP
const Content = db.connection.collection('content')
const docs = [{
// some content...
}]
await Content.insertMany(docs)
// EXECUTE
const result = await resolvers.Query.articleGetContent({}, {
id: '123,
language: 'en'
}, {
token
})
// VERIFY
expect.assertions(1)
expect(result).toBeDefined()
})
})
})
resolver
import { articleGetContent } from '../models/article'
export default {
Query: {
articleGetContent: async (obj, { id }, { token }) => articleGetContent(id, token)
}
}
This is how my db class looks like
db.js
export default class Db {
constructor (uri, callback) {
const mongo = process.env.MONGO || 'mongodb://localhost:27017'
this.mongodb = process.env.MONGO_DB || 'testing'
this.gfs = null
this.connection = MongoClient.connect(mongo, { useNewUrlParser: true })
this.connected = false
return this
}
async connect (msg) {
if (!this.connected) {
try {
this.connection = await this.connection
this.connection = this.connection.db(this.mongodb)
this.gfs = new mongo.GridFSBucket(this.connection)
this.connected = true
} catch (err) {
console.error('mongo connection error', err)
}
}
return this
}
async disconnect () {
if (this.connected) {
try {
this.connection = await this.connection.close()
this.connected = false
} catch (err) {
console.error('mongo disconnection error', err)
}
}
}
async dropDB () {
const Content = this.connection.collection('content')
await Content.deleteMany({})
}
}
Related to the second question I hope you've found some issues on github about it.
In general, the issue is described in the debug log.
Jest works with promises, as a result, you shouldn't leave any async operations in any status except resolved.
In your case, you have your DB connection opened so you need to implement another method disconnect for your DB class, this link to docs will help you, but I guess you have it already as it's not the full db.js file ( I see some custom method dropDB. Main idea here is to have it in afterAll hook:
afterAll(() => db.disconnect());
Great example at the bottom of the page
What about the first question, it really depends on what you are doing in your method dropDB. If you're running method for dropping collection, you could store the reference to this collection somewhere outside and use it as it will automatically create the new one, but it would be great to see this method.
Additionally, your async test was created in a wrong way, you could read more here for example in my Update. You need to run this function in the beginning of the test: expect.assertions(number)
expect.assertions(number) verifies that a certain number of assertions
are called during a test. This is often useful when testing
asynchronous code, in order to make sure that assertions in a callback
actually got called.

sinon stub not restoring properly if the stubbing method is deconstructed

Given the test codes below:
subAuthCall:
const sinon = require('sinon')
const sandbox = sinon.createSandbox()
function stubSuccessCall() {
return sandbox.stub(authorization, 'authorize').returns({enabled: true});
}
function stubFailedCall() {
return sandbox.stub(authorization, 'authorize').returns({enabled: false});
function restoreSub() {
sandbox.restore();
}
in the authorization.js file, I have:
function authorize(data) {
return data.enabled;
}
module.exports = {
authorize
}
and then in the middleware, I have:
const {authorize} = require('./authorization')
async function check() {
//import auth data
console.log(authorize(data))
if (authorize(data)) {
//resolve to true
} else {
//reject
}
}
Then in the test case, I called:
afterEach(authorizationStub.restorStub);
describe('auth testing', () => {
it('test successful', () => {
authorizationStub.stubSuccessCall();
return check().then(res => {expect(res.result).to.equl(true)});
})
it('test failed', () => {
authorizationStub.stubFailedCall();
return check().then(res => {expect(res.result).to.equl(false)});
})
})
It's a overly simplified auth logic and test case. The weird problem I had is that if I run both test cases, it prints out:
1 - test successful
true // from console.log(authorize(data))
2 - test failed
true // from console.log(authorize(data))
The 1st test case passed and the 2nd one failed (because the stubbing didn't return the right result)
but in the test failed, case, it supposed to return false as how I stub it in stubFailedCall, but it still has the same result in stubSuccessCall. I have verified the restoreStub is called.
I accidentally came across the fix: In the middleware, I used to have:
const {authorize} = require('./authorization')
...
but if I changed this to:
const auth = require('./authorization')
and then in the codes, instead of:
authorize(data)
I do:
auth.authorize(data)
This will work - both test cases will pass without any other changes.
My question is, why sinon stub/restoring stub didn't work if I deconstruct the authorize call in the middleware, but if I use an object to make the call, it will work? What's the mechanism behind this?

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