tests: Playwright spec for explorer URL state round-trip (closes #209)

[rdhyee]

Closes #209. CI-safe Playwright specs covering the URL state contract slices fixed by PRs #203, #205, #210, #212.

What this adds

New file: tests/playwright/url-roundtrip.spec.js. Five tests:

#	Test	Regression for
1	Point-mode deep-link with mode=point enters point mode	Bug B fix in #203 (omitted heading)
2	Low-alt deep-link WITHOUT mode=point enters point mode	#207 item 4 (altitude-authoritative)
3	Sub-threshold pan updates URL hash via moveEnd	#205 (percentageChanged suppressed events)
4	URL round-trips across browser contexts	#203 + #205 combined
5	h3 hashchange with invalid cell clears _globeState.selectedH3	#207 item 6 (boot/hashchange asymmetry)

What's intentionally NOT covered

• Search-result row click selection (explorer: URL state contract micro-fixes (post-#203 follow-ups) #207 item 8). Requires working FTS data; depends on substrate the spec shouldn't have to set up. Deferred to a manual smoke or a separate spec once a fixture dataset is available.
• Cold-cache live-site investigation. tests/playwright/url_roundtrip_investigation.js remains as a manual diagnostic — too slow and network-sensitive for CI. The new spec covers the same surface against the Quarto preview.
• Filter URL state (?sources=, ?material=, etc.). Separate UX path; could be a follow-up spec.

Notes on the implementation

• Uses waitForPointModeSettled (waits for the phase message's "Click one for details." text) instead of waitForMode for the no-mode=point cases — waitForMode alone can match a transient mode flip during boot (the dual-mode-state anomaly being addressed structurally in explorer: refactor URL/mode state management (centralize writers, collapse dual mode) #208).
• test.setTimeout(360000) per describe block — cold-cache point-mode boot can take 60–90s per explorer: 60–90 s 'no dots' window on cold-cache deep-link to point mode (DuckDB-WASM 1.24.0 falls back to full HTTP read) #190, and the round-trip test opens multiple fresh contexts each paying the cost.
• Helpers (waitForMode, waitForPointModeSettled, snapshot) are inlined in the spec file rather than shared with explorer-helper.spec.js. They overlap a bit; a future spec consolidation could DRY them up but the cost is small and the helpers are simple.

Verification

All 5 tests pass against localhost (Quarto preview of current main) in ~1m 24s on this machine. Output:

✓  1 deep-link with mode=point enters point mode (Bug B from #203) (12.9s)
✓  2 deep-link with low altitude AND no mode=point still enters point mode (#207 item 4) (12.1s)
✓  3 sub-threshold pan updates URL hash via moveEnd (#205) (15.9s)
✓  4 URL round-trips across browser contexts (#203 + #205 combined) (38.6s)
✓  5 h3 hashchange with invalid cell clears selectedH3 (#207 item 6) (7.0s)

Risks

• CI runtime: ~1.5 min added to the test job. Slower than other specs but mostly bounded by Cesium / DuckDB-WASM cold-start cost.
• Flakiness from cold-cache timing: the 360s test timeout is generous but assumes the test machine can render Cesium reasonably quickly. CI machines vary.
• Tests run against localhost:5860 by default (via TEST_URL env). Same convention as the existing specs; no CI-config changes needed.

🤖 Generated with Claude Code

[rdhyee]

Codex review — round 1

Self-contained Codex review (no shared context with our session). Pasting verbatim per the iterative-review pattern.

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Summary

The specs are useful, but I would not approve this as-is if the PR title/body says closes #209. The biggest test-design issue is Test 5: it can pass without proving that stale selectedH3 state was cleared.

Per-ask response

1. h3 hashchange spec assertion strength

tests/playwright/url-roundtrip.spec.js:190-213 is too weak. It starts with an invalid h3, so selectedH3 can be null from boot and remain null; that does not prove the hashchange null-result branch clears prior state.

Stronger version: start with a known valid h3, wait until selectedH3 is non-null and preferably canonicalized, then mutate to invalid h3 and assert it clears:

await page.goto(`${EXPLORER_PATH}#v=1&lat=${LAT}&lng=${LNG}&alt=${ALT_CLUSTER}&h3=${VALID_H3}`);
await waitForMode(page, 'cluster');
await page.waitForFunction(async () => {
  const v = await window._ojs.ojsConnector.mainModule.value('viewer');
  return !!v._globeState.selectedH3;
});

await page.evaluate((badH3) => {
  const params = new URLSearchParams(location.hash.slice(1));
  params.set('h3', badH3);
  params.set('heading', '5.0');
  location.hash = '#' + params.toString();
}, '0baadbeeffffffff');

await page.waitForFunction(async () => {
  const v = await window._ojs.ojsConnector.mainModule.value('viewer');
  return v._globeState.selectedH3 === null;
});

That would actually catch a regression in the explorer.qmd:2278-2288 null-result branch.

2. requestRenderMode = false

This is probably OK because Playwright gives each test its own page/context, and Test 4 creates separate contexts explicitly. It should not leak across tests under the current config.

I would still extract a local helper like flyCameraToAndWaitForHash(...), mostly to centralize the pattern and avoid future drift. Cleanup is not necessary unless the same page is reused inside a test.

3. waitForPointModeSettled text match

Yes, tests/playwright/url-roundtrip.spec.js:53-61 makes user-facing copy load-bearing. A copy edit to explorer.qmd:1610-1612 would break these tests without changing behavior.

Better signals:

• expose a test-only/state flag such as viewer._globeState.pointModeSettled
• wait on data/state rather than prose, e.g. viewer._globeState.mode === 'point' plus viewport sample data present
• if staying DOM-based, match the more semantic count phrase already used elsewhere: \d[\d,]*\s+individual\s+samples

4. Timeout

test.setTimeout(360000) at url-roundtrip.spec.js:88 is too broad. The multi-context test may need a high cap, but the h3 invalid-cell test should not be allowed to hang for 6 minutes.

Recommendation:

• keep describe default closer to 120s or 180s
• use test.setTimeout(360000) only inside the round-trip/context-heavy test
• pass tighter helper timeouts in the tests that should settle quickly

5. Helper duplication

Reasonable for this PR, with one caveat. The existing helper file is itself a spec, not a clean support module, so importing from it would be awkward and could accidentally register tests.

I would endorse local duplication for now, but if a third Explorer spec needs waitForMode, phase-message history, or camera flight helpers, move them into tests/playwright/helpers/explorer.js.

6. "closes #209" correctness

I do not think closes #209 is correct.

From the eight listed #209 checklist items, this PR fully covers only:

• sub-threshold pan settles via moveEnd

It partially touches:

• cold-cache / low-alt point-mode deep-link, though the file comment says it intentionally does not try cold-cache deep-links
• h3 behavior, but not the requested valid h3 deep-link round-trip with cluster card hydration and URL persistence

Uncovered:

• pid deep-link + active filters
• valid h3 deep-link round-trip
• search + search_scope
• facet filters
• view=table
• search-result flight

So I would change this to addresses #209 or refs #209, and open/fill a follow-up issue for the remaining matrix.

7. Test 4 race

Yes, url-roundtrip.spec.js:169 should poll the URL hash rather than sleep. The implementation has immediate moveEnd hash writing at explorer.qmd:2117-2120, but timing still depends on Cesium flight completion and render scheduling.

Use waitForFunction:

await pageA.waitForFunction(
  ({ lat, lng }) => {
    const params = new URLSearchParams(location.hash.slice(1));
    return Math.abs(parseFloat(params.get('lat')) - lat) < 0.001 &&
           Math.abs(parseFloat(params.get('lng')) - lng) < 0.001;
  },
  { lat: newLat, lng: newLng },
  { timeout: 10000 }
);

Same improvement applies to Test 3 at url-roundtrip.spec.js:138.

8. selectedPid / selectedH3 field names

They are canonical today; explorer.qmd initializes and writes them directly in many places. But the test is coupled to internal state, not public UI.

Worth a short comment in snapshot() saying these fields are intentionally asserted as the URL-selection backing state. That makes future refactors update the tests consciously instead of treating breakage as mysterious.

9. Other findings

url-roundtrip.spec.js:120 stores before but never uses it. Drop it or assert that the URL changed from before.hash.

url-roundtrip.spec.js:151-187 should close contexts in finally; right now a mid-test assertion failure leaks ctxA/ctxB until Playwright cleanup.

The file header is internally inconsistent: it says the tests “don’t try to drive cold-cache deep-links” at url-roundtrip.spec.js:7-9, while the timeout comment at url-roundtrip.spec.js:86-87 cites cold-cache point-mode boot as the reason for 6 minutes. Tighten that wording.

Verdict

BLOCK