refactor: port to unit tests

[ematipico]

Changes

This PR was vibe coded. I checked the implementation code, but I let the AI porting all tests to be unit.

This PR makes the implementation of i18n more testable.

• Crates a I18nRouter that accepts a context, and emits decisions. Eventually, this decision is given to the middleware, which decides what to do.
• The fallback is even simpler, it's just a function that accepts some parameters and emits decisions

Note

I kept the existing tests for safety. The next PR will remove them (or next commit)

Testing

Green CI

Docs

Not needed

[changeset-bot]

⚠️ No Changeset found

Latest commit: 97a960e

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[codspeed-hq]

Merging this PR will not alter performance

✅ 18 untouched benchmarks

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_{Comparing refactor/testable-i18n-routing (97a960e) with main (5bc2b2c)¹}

Footnotes

1. No successful run was found on main (b958dc9) during the generation of this report, so 5bc2b2c was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩