perf(ci): shard cloud parity across 2 BrowserStack sessions via CDP

[RaananW]

Why

The Parity (Cloud) job runs all parity scenes serially on a single BrowserStack session behind the browserstack-node-sdk-managed tunnel. This is a small, focused subset of #302 that targets the two biggest, lowest-risk wins without the large surface area of that PR (which also replaced the tunnel with a public static site + 233 scene-URL rewrites).

What changed

• Direct CDP, no SDK. Parity connects to remote Chrome via Playwright's connectOptions.wsEndpoint (wss://cdp.browserstack.com/playwright) — no browserstack-node-sdk, no browserstack.yml. Each Playwright worker is its own cloud session, so specs shard across workers.
• Up to 2 parallel sessions. scripts/browserstack-wait.sh grabs up to BSTACK_SESSIONS_REQUIRED (default 2) sessions from the plan, falls back to fewer when the plan is busy, exports CIWORKERS, and retries on queue-size-exceeded.
• Tunnel kept (unlike perf(ci): cut cloud parity time — public static site + sharded BrowserStack (CDP) #302). A BrowserStack Local tunnel is started by the config's globalSetup (config/browserstack-local-tunnel.ts) so the remote browser still reaches the local Vite dev server. Specs keep using goto("/sceneN.html") unchanged.
• Perf job untouched. Perf still uses the SDK + config/browserstack.yml + tunnel.

Files

• config/playwright.parity-cloud.config.ts — SDK launch → CDP connectOptions; workers from CIWORKERS; fullyParallel; trace: "off" (the wsEndpoint embeds the access key).
• config/browserstack-cdp.ts (new) — shared CDP endpoint builder + localIdentifier.
• config/browserstack-local-tunnel.ts (new) — globalSetup that starts/stops the Local tunnel; no-op without credentials.
• scripts/browserstack-wait.sh (new) — session grabber (default 2).
• package.json — add browserstack-local dep; test:parity-cloud no longer wraps the SDK.
• azure-pipelines.yml — run parity via browserstack-wait.sh with BSTACK_SESSIONS_REQUIRED=2 and a per-build BSTACK_LOCAL_IDENTIFIER.
• TESTING.md — document the CDP/sharded setup.

Expected impact

At 2 sessions the parity job should be roughly 2× faster, with no changes to engine src, scenes, or goldens.

Verification

• Both config paths load via playwright test --list (local-fallback and CDP with creds → 213 tests).
• bash -n scripts/browserstack-wait.sh clean; azure-pipelines.yml valid YAML.
• prettier --check clean on changed files; confirmed Playwright 1.58 runs the function returned by globalSetup as teardown, so the tunnel is stopped.
• Full parity suite needs BrowserStack credentials, so it runs in CI only.

Notes / follow-ups

• Touches tests/configs/pipeline only (no engine src), so parity/bundle guardrails aren't required by repo rules; perf is never run by agents.
• The CDP wsEndpoint embeds the access key; trace is forced off. A dedicated secret-redaction step for published reports (as in perf(ci): cut cloud parity time — public static site + sharded BrowserStack (CDP) #302) could be a later hardening follow-up.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Copilot]

Pull request overview

This PR speeds up the Parity (Cloud) Azure Pipelines job by switching it from an SDK-managed single BrowserStack session to direct CDP connections with Playwright, enabling the parity specs to shard across up to 2 parallel BrowserStack sessions while keeping the Local tunnel approach (remote browser still reaches the local Vite dev server).

Changes:

• Replace browserstack-node-sdk usage in cloud parity with Playwright connectOptions.wsEndpoint (CDP) and drive worker count via CIWORKERS.
• Add a browserstack-wait.sh helper to poll plan capacity, pick an available session count, export CIWORKERS, and retry on queue contention.
• Add shared BrowserStack CDP helpers + a Playwright globalSetup to start/stop a browserstack-local tunnel; update CI + docs accordingly.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
TESTING.md	Documents the new CDP + sharded parity-cloud setup and session-wait invocation.
scripts/browserstack-wait.sh	New capacity-polling wrapper that selects an available session count and exports CIWORKERS.
pnpm-lock.yaml	Locks the added browserstack-local dependency.
package.json	Updates parity-cloud script to run Playwright directly; adds browserstack-local.
config/playwright.parity-cloud.config.ts	Switches parity-cloud to CDP wsEndpoint, enables parallel workers, and wires in globalSetup.
config/browserstack-local-tunnel.ts	New Playwright globalSetup to manage the BrowserStack Local tunnel lifecycle.
config/browserstack-cdp.ts	New shared helpers to build the CDP endpoint and keep localIdentifier consistent.
azure-pipelines.yml	Runs parity-cloud via the wait script, sets sessions required + per-build local identifier.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

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[bjsplat]

Bundle Size Changes

Decreases

Package	Current	Master	Change
Scene 179 - Clustered Sponza Lights scene179	47 KB	73 KB	-26 KB

Sizes rounded to nearest KB. Run pnpm build:bundle-scenes locally to verify.

[bjsplat]

Lab - Static Site

Open deployed site

_{Build 20260706.9 - merge @ ca7c72f}