testing: add unit tests for useCurrencyConverter

[nanaf6203-bit]

Summary

src/hooks/useCurrencyConverter.ts has no tests even though it touches rate fetching, caching, and storage.

Affected area

src/hooks/useCurrencyConverter.ts

Steps to reproduce

There is no test file.

Expected behaviour

Cover fetch failures, stale data, network reconnect, and storage re-hydration.

Acceptance criteria

• Branch coverage ≥85 %.

[fwseyi]

@fwseyi has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I can handle this. I’ll add a comprehensive unit test suite for useCurrencyConverter, covering exchange-rate fetching, caching behavior, storage rehydration, fetch failures, stale cache handling, and network reconnection scenarios, with a target of at least 85% branch coverage.

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

[jonathanayubausara-a11y]

@jonathanayubausara-a11y has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi Maintainer, I'd love to work on this issue.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @jonathanayubausara-a11y to this issue.

[drips-wave]

Congratulations, @jonathanayubausara-a11y! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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[drips-wave]

This issue has been completed by @jonathanayubausara-a11y as part of the Stellar Wave Program's 6th Wave 🥳

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