[Web] Add Playwright harness and checkout happy path

[kiftio]

What changes are you making?

Web tests currently run in a simulated DOM. Add a Playwright harness that loads the built web package in Chromium and exercises a real popup and cross-origin protocol exchange. The first happy-path test checks presentation, the ready handshake, public start/complete events and checkout snapshots, and host-driven closing.

The synthetic checkout needs no storefront configuration. Telemetry is disabled and unexpected external requests are blocked and fail the test. The private test package lives in platforms/web/test/e2e and shares the existing web workspace and lockfile, following the React Native integration-harness pattern.

Run the suite through dev web e2e or dev web check. Web CI runs it and retains reports and failure traces. The existing web path filter covers the harness. dev up provisions Chromium using Playwright’s idempotent installer; dev web e2e install remains available for targeted setup or recovery.

For this initial increment, the browser suite shares the Web CI job to reuse dependency setup and the SDK build. The latest PR run spent about 24 seconds installing Chromium and 1.7 seconds running Playwright; the full Web job took about 55 seconds. dev web build and dev web test remain independent of browser tests. As coverage grows, especially with multiple browsers or real checkout flows, a separate required Web E2E job would allow independent execution and retries, following the native E2E pattern.

Builds on Mark Murray’s harness and ideas in #418, with a focused initial test for the current lifecycle API. Error cases, further presentation coverage, origin validation, and Firefox/WebKit coverage are follow-up work.

How to test

dev up
dev web e2e

Validated locally with shadowenv exec --:

• dev web check: lint, 304 unit tests, E2E typecheck, Chromium happy path, package build and verification, and sample build.
• Frozen-lockfile workspace installation and packed-files snapshot.
• Chromium provisioning command from the new harness path. Full dev up also passed before the directory move.
• Changed-file filter and native E2E run-plan tests: 69 tests passed.
• git diff --check.

Setup and harness documentation: platforms/web/test/e2e/README.md.

The normal PR CI run after publishing passed on the current commit, including the Linux Web job, Chromium happy path, report upload, and CI Required.

Stack

• [Web] Add checkout page objects and structured browser coverage #866
• [Web] Add Playwright harness and checkout happy path #855

[github-actions]

Web — Coverage Report

Lines	Statements	Branches	Functions
	95.16% (374/393)	84.32% (199/236)	97.08% (100/103)

[github-actions]

Package Size

Platform	Artifact	Base	Head	Delta
Web	npm tarball	89.4 KiB	89.4 KiB	+21 B

Web file breakdown

File	Base	Head	Delta
dist/index.js.map	249.1 KiB	249.1 KiB	0 B
dist/index.d.ts	47.9 KiB	47.9 KiB	0 B
dist/custom-elements.json	47.5 KiB	47.5 KiB	0 B
dist/index.js	33.3 KiB	33.3 KiB	0 B
README.md	20.1 KiB	20.1 KiB	0 B
package.json	3.1 KiB	3.2 KiB	+126 B
LICENSE	1.1 KiB	1.1 KiB	0 B

Measured from the PR base SHA and PR head SHA. The file breakdown shows uncompressed sizes within each package artifact, so individual files do not sum to the compressed artifact total. This comment reports package artifact sizes only; it is not a final app binary-size report.