fix(browserstack-service): land beforeEach/afterEach custom tags in WDIO+Mocha (SDK-6843)

[anish353]

Proposed changes

Fixes test-level custom-metadata hook timing in WebdriverIO + Mocha: browser.setCustomTags(key, value) called from beforeEach or afterEach hooks was lost — only in-test-body calls reached the test's TestRunFinished event. With this PR, tags set in beforeEach, the test body, and afterEach all land on the test (parity with the Java SDK, where @Before/@After tags work).

Root causes

• beforeEach: WDIO runs it before beforeTest establishes the tracked per-test instance, so the call had no test context and was dropped ("called outside a resolvable test context").
• afterEach: WDIO dispatches the TestRunFinished (TEST/POST) send at afterTest, which fires before the user's afterEach — the tag merged into local state after the event was already sent.

Fix (Binary/CLI flow, mocha-gated)

• Hook-window tracking (customTags.ts, service.ts): the service's beforeHook/afterHook record which Mocha hook window is open (before each / after each / before all / after all, classified from the hook title) — the CLI framework never sees these hooks by itself.
• Routing (cli/modules/customTagsModule.ts): tags set in a before-each/before-all window buffer for the upcoming test and flush at test start; tags set in after-each/after-all or the test body merge into the current test. (This also fixes a latent bug where a 2nd+ test's beforeEach tags silently merged into the previous test's already-sent instance.)
• Deferred send (cli/modules/testHubModule.ts, service.ts): the TEST/POST TestRunFinished send is stashed instead of sent at afterTest, and flushed at the next test's first event (each test gets a fresh instance, so the stashed reference stays valid) or at worker end via service.after(). The payload serializes from the instance's live data at send time, so afterEach merges are included; uuid/started_at/ended_at are already stamped in the data (no drift), and an explicit state override keeps the event labeled TEST/POST even if LOG events move the instance's current state.

Scope: Binary/CLI flow. The legacy Direct/Listener handler is unchanged.

Jira: SDK-6843.

Types of changes

• Polish (an improvement for an existing feature)
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (improvements to the project's docs)
• Specification changes (updates to WebDriver command specifications)
• Internal updates (everything related to internal scripts, governance documentation and CI files)

Checklist

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works — verified live end-to-end (see below); no unit-test hook exists for the module's framework-tracking path
• I have added the necessary documentation (if appropriate) — N/A
• I have added proper type definitions for new commands (if appropriate) — N/A (no API-signature change; setCustomTags stays (key, value))

Backport Request

• This change is solely for v9 and doesn't need to be back-ported
• Back-ported PR at #XXXXX

Further comments

Why defer the send instead of re-sending: TestRunFinished is one-shot per test; re-sending would risk duplicate test runs. Deferring only the transmission (not the event bookkeeping) keeps every other TEST/POST observer (Automate session status, accessibility, Percy) running at afterTest exactly as before — only the TestHub gRPC send moves past the hook window.

Verification (live, real BrowserStack sessions, 2-test spec sharing beforeEach/afterEach):

• Test 1 custom_metadata on the wire:
  testTagBefore=["Browserstack","Before"] (beforeEach), testTagInTest=["Browserstack"] (body), and the same-key union testTagAfter=["Browserstack","After","BrowserstackAfterChanged"] (body + afterEach, existing-first order).
• Test 2 got its own beforeEach/afterEach tags (testTagBefore, testTagAfter=["BrowserstackAfterChanged","After"] via the worker-end flush) with zero cross-test leakage in either direction.
• Exactly one TestRunFinished per test reached the binary (deferral drops nothing); the deferral/flush debug trail shows 2× stash + 2× flush (next-test boundary and worker end).

History note: earlier commits on this branch added, then removed, build-level custom metadata (setCustomTags(k, v, true)) — dropped because build-level custom_metadata is not a documented BrowserStack feature (the documented build-level path is the buildTag config, which WDIO already supports). The PR's net diff is the test-level hook-timing fixes only. Squash-merge recommended.

Reviewers: @webdriverio/project-committers

🤖 Generated with Claude Code

[anish353]

Superseded by #3, which re-bases this change onto main so test-level custom-metadata hook handling can release independently of the title-based-TC PR (webdriverio#15378). This branch's name ("build-level") was also misleading — build-level was dropped. Closing in favor of #3 (branch test_level_custom_metadata).