v4 upgrade: Build failing from lint issues in tests

[imjoshdean-tc]

So something new that I've noticed after working on upgrading one of my projects from v3 to v4 is that linting issues that are in my *.spec.js files are causing builds to fail when I run react-scripts build.

Is this intentional and I missed something in the upgrade guidelines? My (potentially unwarranted) concern is that somehow my tests are ending up in the build.

My guess is that I can disable this with an .eslintignore file, but would love to know if that is the best way forward.

[ChristianMurphy]

It is intentional from the changelog https://github.com/facebook/create-react-app/releases/tag/v4.0.0

We've upgraded to ESLint 7 and added many new rules including some for Jest and React Testing

ESLint is run as part of react-scripts build to check the code.

Disabling ESLint for a folder or overall is an option (see #10021), but may not be a good idea, as the ESLint rules CRA provides by default highlight potential errors.