feat(testing): support deep piercing with Puppeteer

[christian-bromann]

What is the current behavior?

Currently Stencil only supports piercing Shadow DOMs one level deep. However users might want to look up more nested components. This is already supported by Puppeteer, e.g. using Puppeteer primitives, you can do:

const span = await page.$('cmp-a >>> cmp-b >>> cmp-c >>> span');
expect(await span.evaluate((el) => el.textContent)).toBe('I am in component C');

However Stencil wraps this API for convenience purposes and had a custom implementation for piercing through the Shadow DOM. Likely this feature was implemented in Puppeteer after this interface was implemented in Stencil.

I mentioned on our Jam session that I had concerns about limitations about this approach. As we are now fully rely on Puppeteers implementation for piercing, these limitations are gone.

What is the new behavior?

This patch makes piercing through Shadow DOM available using Stencil primitives.

Documentation

Does this introduce a breaking change?

• Yes
• No

Testing

Add some e2e tests for this.

Other information

n/a

[github-actions]

--strictNullChecks error report

Typechecking with --strictNullChecks resulted in 1138 errors on this branch.

That's 1 fewer than on main! 🎉🎉🎉

reports and statistics

Our most error-prone files

Path	Error Count
src/dev-server/index.ts	37
src/dev-server/server-process.ts	32
src/compiler/prerender/prerender-main.ts	22
src/testing/puppeteer/puppeteer-element.ts	21
src/runtime/client-hydrate.ts	20
src/screenshot/connector-base.ts	19
src/runtime/vdom/vdom-render.ts	17
src/dev-server/request-handler.ts	15
src/compiler/prerender/prerender-optimize.ts	14
src/compiler/sys/stencil-sys.ts	14
src/sys/node/node-sys.ts	14
src/compiler/prerender/prerender-queue.ts	13
src/compiler/sys/in-memory-fs.ts	13
src/runtime/connected-callback.ts	13
src/runtime/set-value.ts	13
src/compiler/output-targets/output-www.ts	12
src/compiler/transformers/test/parse-vdom.spec.ts	12
src/compiler/transformers/transform-utils.ts	12
src/compiler/transpile/transpile-module.ts	12
src/mock-doc/test/attribute.spec.ts	12

Our most common errors

Typescript Error Code	Count
TS2322	361
TS2345	345
TS18048	204
TS18047	82
TS2722	37
TS2532	24
TS2531	21
TS2454	14
TS2790	11
TS2352	9
TS2769	8
TS2538	8
TS2416	7
TS2493	3
TS18046	2
TS2684	1
TS2430	1

Unused exports report

There are 14 unused exports on this PR. That's the same number of errors on main, so at least we're not creating new ones!

Unused exports

File	Line	Identifier
src/runtime/bootstrap-lazy.ts	21	setNonce
src/screenshot/screenshot-fs.ts	18	readScreenshotData
src/testing/testing-utils.ts	198	withSilentWarn
src/utils/index.ts	145	CUSTOM
src/utils/index.ts	269	normalize
src/utils/index.ts	7	escapeRegExpSpecialCharacters
src/compiler/app-core/app-data.ts	25	BUILD
src/compiler/app-core/app-data.ts	115	Env
src/compiler/app-core/app-data.ts	117	NAMESPACE
src/compiler/fs-watch/fs-watch-rebuild.ts	123	updateCacheFromRebuild
src/compiler/types/validate-primary-package-output-target.ts	61	satisfies
src/compiler/types/validate-primary-package-output-target.ts	61	Record
src/testing/puppeteer/puppeteer-declarations.ts	485	WaitForEventOptions
src/compiler/sys/fetch/write-fetch-success.ts	7	writeFetchSuccessSync

[github-actions]

PR built and packed!

Download the tarball here: https://github.com/ionic-team/stencil/actions/runs/8456708621/artifacts/1364129550

If your browser saves files to ~/Downloads you can install it like so:

unzip -d ~/Downloads ~/Downloads/stencil-core-4.13.0-dev.1711563561.5fdc5b9.tgz.zip && npm install ~/Downloads/stencil-core-4.13.0-dev.1711563561.5fdc5b9.tgz

[christian-bromann]

@rwaskiewicz this is no ready for review.

[christian-bromann]

Raised a subsequent PR to update the docs: ionic-team/stencil-site#1383