Cypress for Electron - Using FS - node.js

I am using Cypress to test my Electron application.
Since Cypress uses the browser mode, FS is not supported.
So I am getting this error:
Error in mounted hook: "TypeError: fs.existsSync is not a function"
And I found this on the documentation:
https://docs.cypress.io/api/commands/task.html#Event
So I added this on my test:
it('Sample test', () => {
cy.task('readSettingsJson', settingsFolder).then((content) => {
// This can print the JSON file contents correctly
console.log('content = ' + content)
})
})
And on my plugins/index.js:
on('task', {
readSettingsJson(foldername) {
if (!fs.existsSync(foldername)) {
fs.mkdirSync(foldername, { recursive: true })
// some command to copy the file
} else {
// This is what I am testing at this moment
return fs.readFileSync(path.join(filename, '/settings.json'), 'utf8')
}
return null
}
})
However, it doesnt seem to work. I still get the error:
Error in mounted hook: "TypeError: fs.existsSync is not a function"
And despite the test printing the json file correctly, my app still can't load the JSON file.
Am I missing anything? Help please!

Cypress support for Electron apps are in very early alpha release:
https://www.cypress.io/blog/2019/09/26/testing-electron-js-applications-using-cypress-alpha-release/
As an alternative, try using Spectron, which is the testing framework that is currently recommended by Electron team:
https://www.electronjs.org/spectron

Related

Evaluate a Cypress configuration file

In my build scripts I need to evaluate a Cypress configuration file. I'm using the following script:
let appdata = process.env.LOCALAPPDATA;
let version = `11.0.1`;
let src = `${appdata}/Cypress/Cache/${version}/Cypress/resources/app/node_modules/#packages/data-context/src`;
const DataContext = require(`${src}/DataContext.js`).DataContext;
const ProjectConfigManager = require(`${src}/data/ProjectConfigManager.js`).ProjectConfigManager;
(async() => {
const ctx = new DataContext({
schema: null,
schemaCloud: null,
modeOptions: "run",
appApi: {},
localSettingsApi: {},
authApi: {
} ,
configApi: {
},
projectApi: {
} ,
electronApi: {
} ,
browserApi: {
},
})
let configManager = new ProjectConfigManager({
ctx,
configFile: 'C:\\work\\sample\\sample.config.ts',
projectRoot: 'C:\\work\\sample',
handlers: [],
hasCypressEnvFile: false,
eventRegistrar: null/*new EventRegistrar()*/,
onError: (error) => {},
onInitialConfigLoaded: () => {},
onFinalConfigLoaded: () => Promise.resolve(),
refreshLifecycle: () => Promise.resolve(),
})
configManager.configFilePath = "sample.config.ts"
configManager.setTestingType('e2e')
let cfg = await configManager.getConfigFileContents()
console.log(JSON.stringify(cfg));
})();
It works well for Cypress 10 version.
However, Cypress 11 has introduced some changes that break this script. Though I adjusted the paths, I'm still unable to make it work again.
It currently fails with this error:
Error: Cannot find module 'C:\Users\mbolotov\AppData\Local\Cypress\Cache\11.0.1\Cypress\resources\app\node_modules\graphql\index'. Please verify that the package.json has a valid "main" entry
How can I fix this problem (without making changes to the Cypress installation)?
OR
Is there any other way to evaluate a Cypress configuration file (say from the command line) and obtain its values?
The exact usage is unclear to me, but making some assumptions - a nodejs script in the /scripts folder of the project can compile and resolve the config using the Cypress module API.
It would need a test to run, a "null-test" can be generated from inside the script.
Note, the null-test must conform to the spec pattern of the project (below it's the std .cy.js)
const cypress = require('cypress')
const fs = require('fs')
fs.writeFileSync('../cypress/e2e/null-test.cy.js', 'it("", ()=>{})')
cypress.run({
project: '..',
spec: '../cypress/e2e/null-test.cy.js',
quiet: true
}).then(results => {
if (results.status === 'failed') {
console.log(results)
} else {
console.log(results.config.resolved) // output resolved config
}
})
I haven't attempted to duplicate everything you have in your code, as it's using Cypress internals and not publicly documented.
This may be because of Changelog 11.0.0
We have also massively improved our startup performance by shipping a snapshot of our binary instead of the source files.
Looking inside the cache folder for v10.11.0 (${process.env.CYPRESS_CACHE_FOLDER}/10.11.0/Cypress/resources/app), the /node_modules is fully populated and /node_modules/graphql/index.js exists.
But in v11.0.1 /node_modules/graphql is not fully populated.

Cypress cannot find the browser when ran from module api

I'm trying to run a pretty simple test through cypress , with chrome , through module-api. I don't want to run the tests through their launcher but from node as I'll start the tests through mocha framework.
The tests at least can start with electron , but can't find the elements I'm trying to click. It works with chrome through the launcher - with npx cypress run --browser chrome. Though when I use the module-api I get this error:
Can't run because you've entered an invalid browser name.
Browser: electron was not found on your system or is not supported by Cypress.
Cypress supports the following browsers:
Here's my config:
const { defineConfig } = require('cypress')
module.exports = defineConfig({
fixturesFolder: false,
e2e: {
experimentalSessionAndOrigin: true, // multi-domain tests as there could be an Auth0 authentication
setupNodeEvents(on, config) {
return {
browsers: config.browsers.filter(
(b) => {
if (b.name == 'chrome') {
console.log(b); // print info about the browser
return b;
}
}
),
}
}
},
})
The file that starts the test (e.g. example-test.js):
const cypress = require('cypress')
return cypress.run({
spec: './cypress/e2e/simple-login.cy.js'
}).then((result) => {
console.log(result);
process.exit(0);
})
I'm starting it with:
node example-test.js
(the simple-login just enters a password , email and clicks a button and it works when I use cypress run ..).
The console log prints correctly the information about the browser ,though still there's an error. Any idea how this can be fixed?
Your return value in setupNodeEvents() is only returning chrome type browsers, so the error
Browser: electron was not found on your system or is not supported by Cypress
is caused by that.
The other side-effect is that other config like experimentalSessionAndOrigin are being removed.
This is how you can log chrome browsers without changing the config
const { defineConfig } = require('cypress')
module.exports = defineConfig({
fixturesFolder: false,
e2e: {
experimentalSessionAndOrigin: true,
setupNodeEvents(on, config) {
config.browsers.forEach((b) => {
if (b.name == 'chrome') {
console.log(b); // print info about the browser
}
})
return config // NOTE unchanged config
}
},
})
Note npx cypress run --browser chrome will work because your filter is allowing chrome browsers to pass, but npx cypress run --browser electron will fail.

Cypress dependency module Stub not working and throwing error while running

I've a below JS File
foo.js
const crudService=require(./pg-db-pool)
function allrecords () {
return 3
}
I've the below cypress test file. I'm planning to mock the crudService.listAllRecords and return a constant value.
testfile.spec.js(original)
const foo = require('./foo')
describe('Testing', () => {
beforeEach(() => {
cy.stub(foo, 'allrecords').returns(10)
})
it('crud test - list', async () => {
const list = foo.allrecords()
expect(list).to.equal('10')
})
})
While executing the test run, it's throwing below error because it was not stubbing correctly.
Oops...we found an error preparing this test file:
cypress/integration/api/routes/utils/foo.js
The error was:
Error: Webpack Compilation Error
./node_modules/pg/lib/native/client.js
Module not found: Error: Can't resolve 'pg-native' in './node_modules/pg/lib/native'
resolve 'pg-native' in './node_modules/pg/lib/native'
Parsed request is a module
using description file: ./node_modules/pg/package.json (relative path: ./lib/native)
Field 'browser' doesn't contain a valid alias configuration
Looked for and couldn't find the file at the following paths:
If I comment the first line of foo.js like below, it works fine.
fool.js(modified)
//const crudService=require(./pg-db-pool)
function allrecords () {
return 3
}
Please help me to stub for the scenario mentioned in original foo.js

Can't use Worker-Loader with Vuejs and Webpack

I am trying to get web workers up and running with Vue cli3 and I'm having trouble getting it to work.
I want to use the following package, worker-loader (and not vue-worker), as it looks well maintained and with more contributions.
Following their tutorial I attempted to modify webpack using the vue cli as follows:
module.exports = {
chainWebpack: config => {
config.module
.rule('worker-loader')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
.end()
}
}
which I hope should match their
{
module: {
rules: [
{
test: /\.worker\.js$/,
use: { loader: 'worker-loader' }
}
]
}
}
which can be read here (https://github.com/webpack-contrib/worker-loader). I tried to follow the documentation for vue cli3 as best I could (found here: https://cli.vuejs.org/guide/webpack.html#simple-configuration).
My component is pretty simple:
import Worker from 'worker-loader!./../../sharedComponents/equations/recurringTimeComposer.js';
<...>
watch:{
recurringPaymentReturnObj: function(newVal, oldVal){
const myWorker = new Worker;
myWorker.postMessage({ hellothere: 'sailor' });
myWorker.onmessage = (e) => {
console.log('value of e from message return', e.data);
}
}
<...>
and in my ./../../sharedComponents/equations/recurringTimeComposer.js file I have:
onmessage = function(e) {
console.log('Message received from main script: ', e.data);
// var workerResult = 'Result: ' + e.data;
// console.log('Posting message back to main script');
postMessage('hello back handsome');
close();
}
I keep getting the error message:
ReferenceError: window is not defined a162426ab2892af040c5.worker.js:2:15
After some googling I came across this post: https://github.com/webpack/webpack/issues/6642, which suggests that the best way to fix this is to add the following to webpack:
output: {
path: path.join(__dirname, 'dist'),
filename: 'bundle.js'
publicPath: 'http://localhost:3000',
globalObject: 'this'
},
After modifying my vue.config.js file I have:
module.exports = {
chainWebpack: config => {
config.module
.rule('worker-loader')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
.end()
config
.output
.path(path.join(__dirname, 'dist'))
.filename('bundle.js')
.publicPath('http://localhost:8080')
.globalObject('this')
}
}
...but still I am getting the window is not defined error.
Does anyone know what is going wrong? It seems to be a weird error in webpack.
Thanks!
EDIT: oh yeah, here is the MDN page for webworker as well: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers.
Being new to Javascript I kept coming back to this issue when trying to use web workers with VueJS. I never managed to make it work with vue-worker or worker-loader.
It is now 2020 and Google has released worker-plugin.
To use it create a module my-worker with two files index.js and worker.js.
index.js creates the module:
const worker = new Worker('./worker.js', { type: 'module' });
const send = message => worker.postMessage({
message
})
export default {
worker,
send
}
worker.js contains the logic:
import _ from 'lodash'
addEventListener("message", async event => {
let arrayToReverse = event.data.message.array
let reversedArray = _.reverse(arrayToReverse)
// Send the reversed array
postMessage(reversedArray)
});
You will also need to update your vue.config.js to use the WorkerPlugin:
const WorkerPlugin = require('worker-plugin')
module.exports = {
configureWebpack: {
output: {
globalObject: "this"
},
plugins: [
new WorkerPlugin()
]
}
};
Now you can use you worker in your components:
Import it with import worker from '#/my-worker'.
Setup a listener in the mounted() lifecycle hook with worker.worker.onmessage = event => { // do something when receiving postMessage }
Start the worker with worker.send(payload).
I set up a starter code on github. I still haven't managed to make HMR work though...
This works for me (note the first line):
config.module.rule('js').exclude.add(/\.worker\.js$/)
config.module
.rule('worker-loader')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
The first line excludes worker.js files, so two loaders wouldn't fight over the same js file
is this what you need ? Vue issue with worker-loader
Updating from the classic vue & webpack config, I found out that to make this one work, I needed to deactivate parallelization.
// vue.config.js
module.exports = {
parallel: false,
chainWebpack: (config) => {
config.module
.rule('worker')
.test(/\.worker\.js$/)
.use('worker-loader')
.loader('worker-loader')
.end();
}
};
I tried add web worker to a vue-cli4 project, and here is what I found:
using worker-loader and make configs in chainWebpack:
HMR works fine, but sourcemap broke, it show babel transformed code.
using worker-plugin as #braincoke mentioned:
HMR broke, but sourcemap works fined. and eslint broke while suggested disable all worker js file eslint instead.
Finally, My solution is tossing vue-cli away, and embrace vite.It support worker natively, and all just go fine now. (I think upgrade webpack to v5 can solve this, but i never tried.)

Is there a jest config that will fail tests on console.warn?

How do I configure jest tests to fail on warnings?
console.warn('stuff');
// fail test
You can use this simple override :
let error = console.error
console.error = function (message) {
error.apply(console, arguments) // keep default behaviour
throw (message instanceof Error ? message : new Error(message))
}
You can make it available across all tests using Jest setupFiles.
In package.json :
"jest": {
"setupFiles": [
"./tests/jest.overrides.js"
]
}
Then put the snippet into jest.overrides.js
For those using create-react-app, not wanting to run npm run eject, you can add the following code to ./src/setupTests.js:
global.console.warn = (message) => {
throw message
}
global.console.error = (message) => {
throw message
}
Now, jest will fail when messages are passed to console.warn or console.error.
create-react-app Docs - Initializing Test Environment
I implemented this recently using jest.spyOn introduced in v19.0.0 to mock the warn method of console (which is accesses via the global context / object).
Can then expect that the mocked warn was not called, as shown below.
describe('A function that does something', () => {
it('Should not trigger a warning', () => {
var warn = jest.spyOn(global.console, 'warn');
// Do something that may trigger warning via `console.warn`
doSomething();
// ... i.e.
console.warn('stuff');
// Check that warn was not called (fail on warning)
expect(warn).not.toHaveBeenCalled();
// Cleanup
warn.mockReset();
warn.mockRestore();
});
});
There is a useful npm package that helps you to achieve that: jest-fail-on-console
It's easily configurable.
Install:
npm i -D jest-fail-on-console
Configure:
In a file used in the setupFilesAfterEnv option of Jest, add this code:
import failOnConsole from 'jest-fail-on-console'
failOnConsole()
// or with options:
failOnConsole({ shouldFailOnWarn: false })
I decided to post a full example based on user1823021 answer
describe('#perform', () => {
var api
// the global.fetch is set to jest.fn() object globally
global.fetch = jest.fn()
var warn = jest.spyOn(global.console, 'warn');
beforeEach(function() {
// before every test, all mocks need to be resetted
api = new Api()
global.fetch.mockReset()
warn.mockReset()
});
it('triggers an console.warn if fetch fails', function() {
// In this test fetch mock throws an error
global.fetch.mockImplementationOnce(() => {
throw 'error triggered'
})
// I run the test
api.perform()
// I verify that the warn spy has been triggered
expect(warn).toHaveBeenCalledTimes(1);
expect(warn).toBeCalledWith("api call failed with error: ", "error triggered")
});
it('calls fetch function', function() {
// I create 2 more mock objects to verify the fetch parameters
const url = jest.fn()
const config = jest.fn()
api.url = url
api.config = config
// I run the test
api.perform()
// I verify that fetch has been called with url and config mocks
expect(global.fetch).toHaveBeenCalledTimes(1)
expect(global.fetch).toBeCalledWith(url, config)
expect(warn).toHaveBeenCalledTimes(0)
});
})
the #perform method I am testing
class Api {
constructor(auth) {
this._credentials = auth
}
perform = async () => {
try {
return await fetch(this.url, this.config)
} catch(error) {
console.warn('api call failed with error: ', error)
}
}
}
You can set the environment variable CI=true before running jest which will cause it to fail tests on warnings in addition to errors.
Example which runs all test files in the test folder:
CI=true jest ./test
Automated CI/CD pipelines such as Github Actions set CI to true by default, which can be one reason why a unit test will pass on your local machine when warnings are thrown, but fail in the pipeline.
(Here is the Github Actions documentation on default environment variables: https://docs.github.com/en/actions/learn-github-actions/environment-variables#default-environment-variables)

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