ci: refactor Cypress sharding due to cloud limits

[martinothamar]

Description

For a good while we've been running into Cypress Cloud limits. Altinn architectural principles are based on open source. Long term we should migrate to Playwright, for now this seemed like a worthwhile alternative to explore.

Verification

• Related issues are connected (if applicable)
• Your code builds clean without any errors or warnings
• Manual testing done (required)
• Relevant automated test added (if you find this hard, leave it and we'll help out)

Summary by CodeRabbit

• Tests

  • End-to-end test runs can now be divided into balanced shards, helping parallel checks complete more efficiently.
  • Test distribution uses historical run times to assign longer-running checks appropriately, with sensible handling for tests without timing data.
  • Invalid shard settings now produce clear validation errors.
  • Parallel test runs report clearer shard information and produce separately identifiable failure logs.

• Bug Fixes

  • Cypress failures now trigger more comprehensive diagnostic collection, while test environments are reliably stopped after each run.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: b7158229-dbe4-4aef-8543-3c6456b1ac37

📥 Commits

Reviewing files that changed from the base of the PR and between 5bc39f2 and 6973a23.

📒 Files selected for processing (1)

• src/App/frontend/test/e2e/cypress-timings.json

Included review availability: Your plan provides up to 2 included reviews per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

Cypress configuration now assigns specifications to duration-balanced shards. Internal and external workflows identify Cypress outcomes, collect conditional diagnostics, upload expanded failure logs, and always stop LocalTest. Timing metadata records updated specification durations.

Changes

Cypress workflows

Layer / File(s)	Summary
Duration-based shard assignment src/App/frontend/scripts/cypress-shard.js, src/App/frontend/test/e2e/cypress-timings.json	configureCypressShard validates shard settings, discovers .ts specifications, applies timing data, and assigns specifications with a greedy duration-balancing algorithm.
Cypress configuration wiring src/App/frontend/cypress.config.js, .github/workflows/app-frontend-cypress.yml	The environment configuration preserves existing Cypress values and passes shard options to configureCypressShard. Internal runs provide shard metadata and use container-specific groups.
Conditional diagnostics and shutdown .github/actions/app-stop-local-env/action.yaml, .github/workflows/app-frontend-cypress.yml	The LocalTest action collects optional diagnostics and always attempts shutdown. Internal and external jobs collect and upload additional logs when Cypress fails.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: ⚪ Minimal · up to 6973a

The current change has no actionable merge-blocking risk identified; it is merge-ready after normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant GitHubActions
  participant CypressConfig
  participant configureCypressShard
  participant Cypress
  participant LocalTestAction
  GitHubActions->>CypressConfig: Set shard total and number
  CypressConfig->>configureCypressShard: Pass config, spec root, timings file, and shard values
  configureCypressShard->>Cypress: Set selected shard specPattern
  Cypress->>GitHubActions: Report Cypress step outcome
  GitHubActions->>LocalTestAction: Stop LocalTest and request diagnostics on failure
  LocalTestAction->>GitHubActions: Write diagnostic logs and complete shutdown

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🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: refactoring Cypress sharding to address cloud limits.
Description check	✅ Passed	The description includes the required sections and explains the Cypress Cloud limit rationale, although the verification checklist remains unchecked.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ci/refactor-cypress-sharding

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