fix: rewrite flaky anvil pagination e2e to test-id locators (#4830)

[frano-m]

Summary

Rewrites e2e/anvil/anvil-pagination.spec.ts end-to-end and removes the three obsolete shared helpers it was the last consumer of. Brings the spec in line with the locator and layout conventions established in anvil-filters.spec.ts.

Spec changes:

• 3 monolithic tests → 9 per-behaviour tests, each named for the single property it asserts.
• Locators switched to getByTestId (TEST_IDS.TABLE_PAGINATION, TABLE_PAGINATION_RESULTS, TABLE_FIRST_CELL, FILTER_ITEM, FILTER_COUNT, SEARCH_ALL_FILTERS) — no .Mui* class top-level locators, no xpath ancestor traversal.
• Pagination transitions now use a triggerActionAndWaitForUpdate(target, action) content-poll primitive: capture the anchor's textContent, run the action, expect.poll until it differs. Replaces waitForLoadState (which doesn't track post-fetch row swap).
• Filter-item clicks use dispatchEvent("click") per the webkit-overlay workaround already adopted in e2e/features/common/filters.ts.
• Shared helper reuse: closeAutocompletePopper from e2e/features/common/filters.ts instead of a raw ESC keypress.
• Conditional test.fail() removed (every test now asserts deterministic outcomes).
• Top-of-file constants block (PAGE_SIZE, PAGES_TO_NAVIGATE, SAMPLE_NAVIGATIONS, FILTER_COUNT_MIN/MAX, ENTITY_URL, ENTITY_URL_WITH_FIRST_CELL) replaces inline magic numbers.
• Helpers alphabetised under a /* ——— helpers ——— */ divider, non-exported.

Why two entity URLs: ENTITY_URL = "/files" is used for 8 of 9 tests (and for the filter-count-in-range search). The "shows different table content on every page" test overrides to "/biosamples" because Files' first cell renders only an icon download button — textContent() returns "" and can't anchor a per-row diff.

Helper cleanup in e2e/testFunctions.ts:

• Deleted testFirstPagePagination, filterAndTestLastPagePagination, testPaginationContent (the spec was their only caller).
• Deleted pagination-only constants PAGE_COUNT_REGEX, MAX_PAGINATIONS, MAX_FILTER_LENGTH.
• Removed the now-unused KEYBOARD_KEYS import. TabDescription, getFirstRowNthColumnCellLocator, filterRegex are retained — used elsewhere.

Closes #4830.

Test plan

• npx tsc --noEmit, npm run lint, npm run check-format pass
• npx playwright test -c playwright_anvil.config.ts e2e/anvil/anvil-pagination.spec.ts — 27/27 across chromium/firefox/webkit (1.1 min)
• npm run test:anvil-cmg — full anvil suite, 132/132 across all three browsers (7.9 min)
• Watch CI for several runs to confirm no Firefox/webkit flakes

Out of scope (potential follow-up)

triggerActionAndWaitForUpdate is a general "perform action, wait for in-place data update" primitive. Other specs (sort, filter-apply) would benefit from sharing it. Hoist to e2e/features/common/utils.ts in a follow-up — deferred to keep this PR scoped.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR rewrites the AnVIL CMG pagination E2E spec to use more focused, test-id-based Playwright assertions and removes obsolete shared pagination helpers that were only used by the old spec.

Changes:

• Replaces 3 broad pagination tests with smaller behavior-specific pagination tests.
• Adds local helpers for pagination parsing, navigation polling, and dynamic filter selection.
• Removes unused legacy pagination helpers/constants from e2e/testFunctions.ts.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
e2e/anvil/anvil-pagination.spec.ts	Rewrites pagination coverage around test-id locators, content-change polling, and per-behavior assertions.
e2e/testFunctions.ts	Removes obsolete shared pagination helpers and related unused imports/constants.

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