i18n-l10n-testing
Skill1 starsChanged 2 months agoMITView on GitHub
Test internationalization and localization — missing keys, text expansion, RTL layout, plural rules, date/number/currency formatting, timezone handling, and locale-dependent bugs. Use when the product ships in more than one language or region.
In this repository34 other files it gives its agents.
- a11y-auditSkill
- api-contract-testingSkill
- autonomous-explorationSkill
- bug-reproSkill
- chaos-resilienceSkill
- ci-wiringSkill
- contract-testing-pactSkill
- coverage-ratchetSkill
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- e2e-authoringSkill
- environment-paritySkill
- exploratory-chartersSkill
- false-positive-hunterSkill
- flake-forensicsSkill
- load-and-stressSkill
- mutation-proofSkill
- never-break-prodSkill
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- qa-triageSkill
- regression-curationSkill
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- responsive-mobile-testingSkill
- risk-mapSkill
- root-cause-protocolSkill
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- state-machine-testingSkill
- test-data-managementSkill
- test-strategySkill
- tracking-testingSkill
- transactional-email-testingSkill
- unit-test-authoringSkill
- visual-regressionSkill
The file
We split this skill into the rules it gives an agent
1 rule. About 0 are common, 0 are distinctive, and 1 is very specific to this project.
≈0
Common · estimate
Many files like this have a rule of this kind.
≈0
Distinctive · estimate
This author's own choices. Worth a look.
1
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Very specific: line 17
Interpolation safety: every placeholder present in every locale.
≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
i18n & l10n
Localization bugs are invisible in the developer's locale and obvious to every affected user.
Automated checks
- Missing keys: fail the build on any key present in the default locale and absent elsewhere, and on any hardcoded user-facing string in the source (lint rule).
- Unused keys: dead translations cost money to maintain.
- Pseudo-localization: render
[!!! Ŧḗẋŧ ḗẋpȧȧƞḓḗḓ !!!]— 40% longer, accented, bracketed. One pass over the app exposes truncation, clipping and untranslated strings at once. - Interpolation safety: every placeholder present in every locale; no locale silently drops
{count}.
Layout under translation
German and Finnish expand ~35% over English; Japanese contracts. Test the longest realistic
translation of every button, tab and label — a nav that wraps to two lines at de-DE is a
layout bug, not a translation issue.
RTL (ar, he, fa) is not a mirror of the CSS: check icon direction, progress and slider
direction, text alignment, punctuation placement, and that numbers and embedded Latin words read
correctly. Use logical CSS properties (margin-inline-start) and assert dir="rtl" renders
without overlap.
Formatting
| Thing | Trap |
| Dates | 03/04/2026 is March 4 or April 3 depending on locale. Assert with Intl.DateTimeFormat, never string equality |
| Numbers | 1.234,56 vs 1,234.56; Indian grouping 12,34,567 |
| Currency | symbol position, spacing, and the fact that formatting is not conversion |
| Plurals | Polish and Arabic have more than two plural forms — test each category, not just 1 and 2 |
| Sorting | locale-aware collation (Intl.Collator), not byte order |
| Names & addresses | no first/last assumption, no fixed postcode format |
Timezones (the silent data corruption)
Store UTC, render local. Test: a user in Pacific/Auckland creating a record at 23:30 local sees
it under today, not yesterday. Run the suite under at least one non-UTC timezone in CI
(TZ=Pacific/Auckland) — it catches an entire class of off-by-one-day bugs that a UTC-only CI
never will.
Output
Per locale: missing keys, truncations found (with screenshots), formatting failures, RTL layout defects. Never report "translations look fine" — report the locales actually exercised.
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