Watch non-spec files for changes and reload specs

[brian-mann]

Many of our users express the need to want to watch files on their system other than the *spec files that we normally watch.

Although we currently watch the spec file you're currently working in (and all of the subdependencies) many of our users express the need to watch other files (like their src files) for e2e/integration tests.

We should do one or both options:

a) give you the ability to specific additional glob paths via cypress.json
b) give you the ability to watch things yourself and signal to cypress when to reload

With our upcoming CLI refactor we could offer something like this...

const chokidar = require('chokidar')
const cypress = require('cypress')

chokidar.watch(FILES)
.on('update', () => {
  cypress.reload()
})

cypress.open()

[jagreehal]

Allowing the user to configure using glob patterns would be awesome.

[collinstevens]

Is this looking to be picked up anytime soon? Having a glob pattern specified for /src/ would be incredibly useful when doing TDD with e2e tests.

[bahmutov]

@collinstevens for now you can use this plugin to watch arbitrary files and rerun the tests https://github.com/bahmutov/cypress-watch-and-reload

[jsphstls]

I only need to re-run tests if Cypress's browser was reloaded by HMR. I do not want Cypress to watch for file changes because HMR already does that for me. HMR actually determines whether the preview window needs a reload since not every src file is a dependency of what is being previewed (such as in a monorepo).

Basically, if the browser window reloaded on its own, re-run the tests.

[Svish]

The method shared by @bkucera doesn't work for me, as there's no such message being printed in the console. Agreeing with @jsphstls, that HMR already keeps track of changes, I decided to try hook into that. Ended up putting the result of the experiment in a simple package, and it seems to work pretty well on my machine with create-react-app at least 🙂👍

It connects to the webpack-dev-server socket and listens for HMR messages of type invalid, and if any arrive, it clicks the restart button after a short delay.

➡ https://www.npmjs.com/package/cypress-hmr-restarter

[kentcdodds]

@Svish's package worked for me 👍 Thanks!

[jpbourgeon]

@cypressTeam

You should consider putting Svish's plugin (or an equivalent) forward. Maybe by making it an official plugin or referencing it somewhere ? It's simple yet effective and helps cypress achieve a true TDD experience:

• I code my test. cypress loads it and it fails (this is bundled into cypress)
• I code the most straightforward way to make my test pass. Cypress (re)loads in real time and informs me when I reach the green point (this is provided by the plugin)
• I refactor my code and focus on keeping my test green (this is too)
• Job done !

[amannn]

I'm also really interested in this feature!

For me the package from @Svish sadly didn't work. I'm using Storybook, maybe the hot reloading is setup differently there.

However I got it working with this snippet:

// Re-run tests when source files change.
// Workaround for https://github.com/cypress-io/cypress/issues/456
Cypress.on('window:before:load', window => {
  const { XMLHttpRequest } = window;
  const originalOpen = XMLHttpRequest.prototype.open;
  XMLHttpRequest.prototype.open = function open(...args) {
    this.addEventListener('load', function load() {
      if (this.url.endsWith('hot-update.json')) {
        cy.$$('.stop', window.top.document).click();
        cy.$$('.restart', window.top.document).click();
      }
    });
    originalOpen.apply(this, args);
  };
});

I noticed that pressing the stop button before restart can be helpful if there's currently a test running.

EDIT: The same works for me with Next.js

[Zwimber]

Anyone coming here for TDD on Angular @bkucera's answer works brilliantly. Adding the "stop" to it from @amannn's answer for this brilliant TDD solution!

Cypress.on('window:before:load', (win)=>{
  const _consoleInfo = win.console.info
  win.console.info = function () {
    if (arguments[0].includes('App updated.')) {
      cy.$$('.stop', top.document).click()
      cy.$$('.restart', top.document).click()
    }
    return _consoleInfo.apply(win.console, arguments)
  }
})

[Svish]

For those here who tried out my cypress-hmr-restarter plugin, I finally got around to add the "pre restart stopping feature" (like @amannn also suggested). Tested it with our app here, and seems to work great. 🙂 👍

[herrmannplatz]

Whoever didnt had luck with @Svish awesome cypress-hmr-restarter plugin might wanna recheck it. It also works now with projects which use webpack-hot-middleware plugin (e.g. gatsby, nuxt?!? havent tested it)

[Svish]

@strowk PR accepted, and also added an option to allow for overriding the URL completely.