Make testing a dependency, not built in

You can’t introduce testing w/o introducing religion, unfortunately. For example, I refuse to test my UI in an environment where I can’t actually render it in a browser and step through problems in real browsers to fix bugs. Asking folks to eject because they don’t like your religion seems a little harsh.

Seems like for testing we ought to be able to have a module on npm called react-scripts-jest, require it in the app’s package.json, and then have npm test be something like:

{
  "scripts": {
    "test": "react-scripts-jest"
  }
}

That would be the default or create-react-app, but other folks can create react-scripts-karma or just roll their own inside the project.

[gaearon]

I understand that increasing the download size is frustrating. However I’m not sure the difference between ~10 MB and ~15 MB download is significant enough to warrant:

• Spending effort into splitting packages and automating additional configuration steps.
• Making already created apps depend on an internet connection for activating some features. (We want to move in the exact opposite direction: #373.)
• Creating an impression that -jest is just one of the options when there is nobody who volunteered to create and support other options.

I am closing this because I don’t see how this is immediately actionable, and who is willing to lead such effort. I am happy to revisit this if:

• Somebody has created a community-supported integration package for another test runner and has demonstrated the willingness to maintain it.
• This person can give us specific feedback on what hooks they would like to see exposed from our side to make such integration easier to support, and is willing to prototype such support as a PR.
• A significant count of our users tell us they are happier with that configuration than the one we ship by default. (Actually, in this case, we might just switch Jest to something else here rather than allow more choice.)

In the meantime, we will be improving Jest in response to our users’s feedback. If this doesn’t answer your concerns, perhaps these alternatives could work better for your use case.

[cpojer]

I think what a lot of people are missing is that we don’t have a single line of config inside of the created app that is related to testing, except of course for the scripts entry to run react-script’s test command. Anyone can just simply install whatever they like and update the test command with no additional overhead. I think this is reasonable.