Feature/dom testing library

[thawkin3]

I've re-written the test suite using Jest and DOM Testing Library. 🎉

This PR is somewhat large, so the following summary of changes should help:

1. Added needed devDependencies: @testing-library/dom, @testing-library/jest-dom, babel-jest, jest, and jest-watch-typeahead
2. Added Jest configuration: jest.config.js file, setupTests.js file, ESLint configuration, Babel configuration, script in package.json, and GitHub workflow configuration
3. Wrote the unit tests in four separate files, one for each exported method: focusable, isFocusable, tabbable, and isTabbable
4. Updated README to mention the Jest unit tests
5. Updated README to no longer mention support for a[xlink:href] attributes
6. Stripped out all Karma-related code: test file, devDependencies, npm script, CI config, Karma config file, README info

Closes #225

PR Checklist

Please leave this checklist in your PR.

• Source changes maintain stated browser compatibility.
• Issue being fixed is referenced.
• Unit test coverage added/updated.
• E2E test coverage added/updated.
• Typings added/updated.
• README updated (API changes, instructions, etc.).
• Changes to dependencies explained.
• Changeset added (run yarn changeset locally to add one, and follow the prompts).

[changeset-bot]

🦋 Changeset detected

Latest commit: 170cdb7

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
tabbable	Patch

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[thawkin3]

@stefcameron Here's my first stab at it! I still have three TODO items that I mentioned in the PR description. The biggest thing that I wanted to confirm with you is that there's no reason to keep the Karma setup around anymore, right? If that's the case, there is a whole bunch of config code that I can strip out.

[idoros]

Looks good!

In regard to the radio button tests, the difference you get from the previous test code is that the new code doesn't attach the fixtures to the DOM. It doesn't break the behavior of most cases, but radio buttons have some query usage to find other group elements. And it make sense that "tabbable" elements would be attached to the DOM.

Not sure the xlink is related to this PR, but adding a[xlink:href] selector to the candidateSelectors list will probably pass your tests.

[stefcameron]

Great work, @thawkin3 , this is looking nice! Thanks for the nice summary in the PR description. I don't see any reason to keep Karma around. There's no other purpose for it beside running tests that are now run by Jest, so it can be ripped out rather than preserved.

[thawkin3]

@stefcameron Awesome, I'll rip out Karma in another commit soon and add it to this PR. This PR is going to get a whole lot bigger with all the deletions!

[thawkin3]

In regard to the radio button tests, the difference you get from the previous test code is that the new code doesn't attach the fixtures to the DOM. It doesn't break the behavior of most cases, but radio buttons have some query usage to find other group elements. And it make sense that "tabbable" elements would be attached to the DOM.

@idoros Well I learned something new today! Thanks for pointing that out. To avoid any other possible surprises, I made sure to actually append all of the test examples to the DOM now. You were spot on, and that fixed the radio button tests.

[thawkin3]

@stefcameron @idoros This behemoth of a PR is ready for a second round of review! Here's a quick summary of what I've changed since our last conversation:

• Stripped out Karma and everything related to it
• Removed the info about the xlink:href attribute in the README
• Fixed the skipped Jest tests
• Updated the Jest tests to actually append the container content to the document body
• Added a patch changeset

[stefcameron]

@thawkin3 Thanks for the updated summary -- so helpful! -- and the additional work. I'll check this out sometime tomorrow.

[stefcameron]

This looks great to me, nice work, thank you! 🎉 I'm really happy to have this repo now also using the Testing Library.

[stefcameron]

@all-contributors add @thawkin3 for test, infra, doc

[allcontributors]

@stefcameron

I've put up a pull request to add @thawkin3! 🎉

[stefcameron]

@all-contributors add @idoros for review

[allcontributors]

@stefcameron

I've put up a pull request to add @idoros! 🎉

[thawkin3]

This looks great to me, nice work, thank you! 🎉 I'm really happy to have this repo now also using the Testing Library.

@stefcameron Thanks! It was fun to work on. I see you've approved this now, so are we good to merge this today? Or are we waiting on the timing for anything else?

[stefcameron]

This looks great to me, nice work, thank you! 🎉 I'm really happy to have this repo now also using the Testing Library.

@stefcameron Thanks! It was fun to work on. I see you've approved this now, so are we good to merge this today? Or are we waiting on the timing for anything else?

I'm merging now. I was just pausing just in case there were any last words. 😄

[stefcameron]

@all-contributors add @idoros for review

[allcontributors]

@stefcameron

I've put up a pull request to add @idoros! 🎉

[thawkin3]

I'm merging now. I was just pausing just in case there were any last words. 😄

Haha thanks!