Set up Vitest and add frontend unit tests

[ogazboiz]

Join our community: https://t.me/+DOylgFv1jyJlNzM0

Description

The frontend has no automated tests at all. The CI job lints and builds but never runs tests. Vitest with React Testing Library would catch regressions in utilities and components.

Test Cases Needed

• frontend/src/utils/amount.ts: fromStroops, toStroops, formatRate, hasValidPrecision
• useStreamEvents hook: connects, receives events, reconnects on disconnect
• Livecounter: increments every second, stops when isPaused prop is true
• StreamCreationWizard: recipient validation error, amount precision validation
• TransactionTracker: all 7 state transitions render correctly
• CancelConfirmModal: confirm and cancel callbacks fire correctly

Files

• frontend/vitest.config.ts (create)
• frontend/src/__tests__/ (create)

Acceptance Criteria

• npm test runs in frontend
• CI frontend job runs tests
• amount.ts utilities at 90%+ coverage

[MerlinTheWhiz]

@MerlinTheWhiz has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Can I work on this?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @MerlinTheWhiz to this issue.

[Spagero763]

@Spagero763 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

i would like to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Spagero763 to this issue.

[drips-wave]

Congratulations, @Spagero763! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

🧑‍💻 @Spagero763: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊