Add overrideConfig option for the react-scripts test script

[cjbuchmann]

Hey all, new contributor here. While I'm really enjoying all of the greatness that this project has to offer, I've run up against a few issues when it comes to testing that would be easily solved by adding my own jest configuration.

Unfortunately the jest configuration appears to be inaccessible to the user, so this branch attempts to allow the user the ability to configure this as needed. From what I understand, I could add my own config by ejecting the react-scripts, but that seems a little too heavy handed.

I also understand that this might go against the core value of 'convention over configuration', so if you'd prefer to avoid this approach, that's fine too.

In particular, I've been following along with jest not running tests inside of /src/node_modules. In my case, I'm also getting import errors SyntaxError: Unexpected token import during testing that is resolved by adding

  "transformIgnorePatterns": [
    "<rootDir>/(node_modules)/"
  ]

to the jest config. But I don't see any way of adding my own config options to the jest config at the present time. (If there is, I'd definitely appreciate that feedback).

Thanks!

Usage

you can define your own config options in a json file
config.json

{
    "transformIgnorePatterns": [
    "<rootDir>/(node_modules)/"
  ]
}

You can then specify that json file in package.json

"test": "react-scripts test --env=jsdom  --overrideConfig=config.json",

the options will be merged with (and can override) the existing configuration options

[gaearon]

Thanks for PR. I don't think we'll be adding this in near future, but we're happy to address individual use cases.

If you have specific issues (e.g. Jest running files that it shouldn't) please file an issue describing those problems and we might just fix them by default for everyone. Thanks!

[cjbuchmann]

thanks @gaearon, but there already is an issue open in regards to my problem. #607 and #1081 address it pretty well.

However, it seems like it's stumbling over road blocks and has been open for a while. If there's anything that I can do to speed that along, please let me know

Thanks!

[gaearon]

Some options are configurable in the next version.
#1830

[gaearon]

Please help beta test the new version that includes this change!
#2172