import { Page } from 'puppeteer/lib/Page';
export class MonitorRequestHelper {
public static monitorRequests(page: Page, on = false) {
if(on) {
page.on('request', req => {
if (['image', 'font', 'stylesheet'].includes(req.resourceType())) {
// Abort requests for images, fonts & stylesheets to increase page load speed.
req.abort();
} else {
req.continue();
}
});
} else {
return true;
}
}
}
I am trying to mock and spy the function to check if it got called at least once.
Also, it would be helpful if some explain me how to mock and spy event-emitter object.
The source code is available on https://github.com/Mukesh23singh/puppeteer-unit-testing
If you want to test that your logic in monitorRequests works, you need to pass in a fake Page object with an event emitter interface that produces a fake request that you can test on.
Something like:
import {spy} from 'sinon';
// Arrange
const fakePage = { on(type, cb) { this[type] = cb; } }; // "event emitter"
const fakeRequest = {
abort: sinon.spy(),
resourceType() { return 'image'; }
};
monitorRequests( fakePage, true );
// Act
// trigger fake request
fakePage['request'](fakeRequest);
// Assert
assert(fakeRequest.abort.called);
Related
I have this simple webworker which does some polling:
import { fetchLatestResults } from '../backend/fetchLatestResults';
let polling = false;
let symbolIds: string[] = [];
const fetchLatest = async () => {
if (!symbolIds.length) {
return;
}
try {
const results = await fetchLatestResults(symbolIds);
self.postMessage(results);
} catch (e) {
// noop for now
}
};
if (!polling) {
polling = true;
fetchLatest();
setInterval(fetchLatest, 10 * 1000);
}
self.onmessage = (e: MessageEvent) => {
symbolIds = e.data;
fetchLatest();
};
How can I unit test this with jest? There is not a lot of code, business logic is extracted, but still there are few cases that I'd like to test, like that fetchLatestResults is not invoked until symbolIds are set, etc. ?
I could probably extract onmessage logic into a function, export it, import it on tests, and call it, but what about postMessage ?
I am scraping a web page using axios and cheerio:
This web page has many links, while more load while scrolling down(like facebook).
I want to scrape each link while scrolling down until I reach the end.
This is a sample of my code:
cheerio = require('cheerio')
axios = require('axios')
function getLink(id) {
return axios(options).then(function(response) {
// Do stuff...
})
}
function scrollDown() {
axios(scrollOptions).then(function(response) {
$ = cheerio.load(response['data'])
isScrollFinished = ($('.page_more').length == 0)
promises = []
newLinks = $('.link') // Get the new links that were loaded while scrolling
newLinks.each(function() {
promises.push(getLink($(this).attr('id')))
})
axios.all(promises).then(responseArr => {
if(isScrollFinished) {
// Exit script
}
})
if(!isScrollFinished) {
scrollDown()
}
})
}
scrollDown()
The problem with this code is that sometimes it doesn't scrape all the links before I exit.
This is because the last axios.all only waits until all the links of the last scrolled page were scraped.
How do I fix this?
I created the promises array as a static variable and only called axios.all on it when the scrolling reached the end:
cheerio = require('cheerio')
axios = require('axios')
function getLink(id) {
return axios(options).then(function(response) {
// Do stuff...
})
}
function scrollDown() {
if (typeof scrollDown.promises === 'undefined') {
scrollDown.promises = [] // Define static variable if undefined
}
axios(scrollOptions).then(function(response) {
$ = cheerio.load(response['data'])
isScrollFinished = ($('.page_more').length == 0)
newLinks = $('.link') // Get the new links that were loaded while scrolling
newLinks.each(function() {
scrollDown.promises.push(getLink($(this).attr('id')))
})
if(isScrollFinished) {
axios.all(scrollDown.promises).then(responseArr => {
// Exit script
})
}
else {
scrollDown()
}
})
}
scrollDown()
Better solutions will gladly be accepted.
I'm trying to create an application with NestJS framework and I'd like to check if a specific Service is in the application context but, the framework default behavior is exiting the process when it doesn't find the Service inside the context.
I've surrounded the get method with try...catch but it doesn't work because of the process.exit(1) execution.
private async loadConfigService(server: INestApplication): Promise<void> {
try {
this.configService = await server.get<ConfigService>(ConfigService, { strict: false });
} catch (error) {
this.logger.debug('Server does not have a config module loaded. Loading defaults...');
}
this.port = this.configService ? this.configService.port : DEFAULT_PORT;
this.environment = this.configService ? this.configService.environment : Environment[process.env.NODE_ENV] || Environment.DEVELOPMENT;
this.isProduction = this.configService ? this.configService.isProduction : false;
}
I'd like to catch the exception to manage the result instead of exiting the process.
Here's what I came up with:
import { NestFactory } from '#nestjs/core';
export class CustomNestFactory {
constructor() {}
public static create(module, serverOrOptions, options) {
const ob = NestFactory as any;
ob.__proto__.createExceptionZone = (receiver, prop) => {
return (...args) => {
const result = receiver[prop](...args);
return result;
};
};
return NestFactory.create(module, serverOrOptions, options);
}
}
Now, instead of using the default NestFactory I can use my CustomNestFactory
Dirty, but it works
Here is my code to solve same issue:
import { ExceptiinsZone } from '#nestjs/core/errors/exceptions-zone';
ExceptionsZone.run = callback => {
try {
callback();
} catch (e) {
ExceptionsZone.exceptionHandler.handle(e);
throw e;
}
};
You may need to override asyncRun() also for other method.
I have some problems with my universal react app runing with saga. I'm rendering react on server. One of my react component executes redux action that should be catched by saga listener on server.
Here is abstract example
// *Header.js*
class Header extends React.PureComponent {
componentWillMount() {
this.props.doAction()
}
....
}
export default connect(null, {doAction})(Header)
// *actions.js*
function doAction() {
return {
type: "action"
}
}
// *saga.js*
function* doAsyncAction(action) {
console.log(action);
}
function* watchAction() {
yield takeEvery("action", doAsyncAction);
}
export default [
watchAction(),
];
// *sagas.js* --> root saga
import 'regenerator-runtime/runtime';
import saga from './saga';
import anotherSaga from './anotherSaga'
export default function* rootSaga() {
yield all([].concat(saga).concat(anotherSaga));
}
// *configureStore.js*
const sagaMiddleware = createSagaMiddleware();
const middleware = applyMiddleware(sagaMiddleware);
...
sagaMiddleware.run(require('./sagas').default);
And after first run node process - it runs and give me console log, but
when I just refresh browser and function doAsyncAction is never executed
Please help, what I'm doing wrong ?
You need to change this:
function doAction() {
return {
type: "action"
}
}
to this:
const mapDispatchtoProps = (dispatch) => {
return {
doAction: () => dispatch({type: "action"})
}
}
export default connect(null, mapDispatchtoProps)(Header)
Client.js setup below for saga middleware:
const sagaMiddleware = createSagaMiddleware()
const createStoreWithMiddleware = applyMiddleware(sagaMiddleware)(createStore)
let store = createStoreWithMiddleware(rootReducers)
sagaMiddleware.run(rootSaga)
The above is implemented where ever you are implementing your store.
in my Node.JS project (a backend for an Angular 5 project) I have created a service that deals with the AWS Authentication... I have called this awsAuthenticationService. All works well but I now need to test it. In my awsAuthenticationService.js I have the following method that has some minor logic and then calls a method provided by the "cognitoIdentityServiceProvider". Here is a snippet of my code (I really have reduced this)
constructor() {
this._cognitoIdentityServiceProvider = new AWS.CognitoIdentityServiceProvider(this.cognitoConfig);
}
toggleUserAccess(userName, type) {
const params = {
Username: userName,
UserPoolId: this.cognitoConfig.userPoolId
};
if (type === null) {
return this._cognitoIdentityServiceProvider.adminEnableUser(params).promise();
}
return this._cognitoIdentityServiceProvider.adminDisableUser(params).promise();
}
As you can see from the toggleUserAccess we pass a few parameters, determine what they are then call the appropriate method. I wish to test this by having a unit test that will call the authenticationService.toggleUserAccess, pass some params and spy on the authenticationService._cognitoIdentityServiceProvider methods to see if they were called. I set it up so...
let authenticationService = require('./awsAuthenticationService');
describe('toggleUserAccess', () => {
beforeEach(() => {
authenticationService._cognitoIdentityServiceProvider = {
adminDisableUser(params) {
return {
promise() {
return Promise.resolve(params);
}
};
}
};
authenticationService._cognitoIdentityServiceProvider = {
adminEnableUser(params) {
return {
promise() {
return Promise.resolve(params);
}
};
}
};
});
it('should call adminEnableUser if the type is null', () => {
authenticationService.toggleUserAccess('TheUser', null);
const spyCognito = sinon.spy(authenticationService._cognitoIdentityServiceProvider, 'adminEnableUser');
expect(spyCognito.calledOnce).to.equal(true);
});
it('should call adminDisableUser if the type is null', () => {
authenticationService.toggleUserAccess('TheUser', '0001');
const spyCognito = sinon.spy(authenticationService._cognitoIdentityServiceProvider, 'adminDisableUser');
expect(spyCognito.calledOnce).to.equal(true);
});
});
My tests aren't passing and I think I have set up my sinon.spys incorrectly - can anyone see what I am doing wrong or give advice please
To stub class of AWS.CognitoIdentityServiceProvider, need to stub with its prototype keyword.
// add require statement for your AWS class
const spyCognito = sinon.spy(AWS.CognitoIdentityServiceProvider.prototype, 'adminDisableUser');
expect(spyCognito.calledOnce).to.equal(true);
Hope it helps