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Software localization teams

LocaleWitness ICU Release Regression Fixtures

Source: this release’s synthetic input → 7 output files. Observed 2026-09-08. Coverage: one example within the supported profile.

LocaleWitness turns ICU message definitions into reproducible regression fixtures you can re-run between releases. It works with an approved en/fr subset of ICU syntax, treating your entries as messages rather than translations, and expands their plural, select, and other branches into concrete cases. The output is a set of branch fixtures tied to a supported runtime profile, so you can confirm that rendering behavior stays stable as messages change over time.

Compile message branches into reproducible runtime tests
Free browser processingNo account requiredDownloadable resultsExplicit supported scope
YOUR WORKSPACE

Turn your input into a checked artifact

Load the synthetic example to explore the format, or choose your own supported JSON file. Processing happens on this device. Your input is not uploaded. The first run downloads the processing engine.

Input template
Load an input to begin. Each workflow also has its own smaller domain limits.

Keep your original source. Unsupported inputs return an explanation. These workflows implement the stated mathematical or file-format checks; they do not establish physical performance, language quality or real-world reliability.

HOW TO USE IT

A repeatable input-to-output workflow

01

Provide your ICU messages and locale data as JSON in the supported en/fr subset.

02

The tool enumerates plural and select branches and records the rendered result for each declared case.

03

You download the branch fixtures and can replay them against your build to detect regressions.

What you receive

  • Branch fixtures per message with declared inputs
  • Rendered case values for the supported runtime profile
  • A summary of covered branches and locales

Supported scope and limits

  • Approved en/fr ICU subset only; other locales or syntax are out of scope
  • Treats entries as messages, not as reviewed translations
  • No linguist review of wording or content
  • Output reflects the supported runtime profile, not every ICU runtime

Read the exact input profile and examples. Start with the supplied template; this release does not guess missing settings.

Example provenance: synthetic source fixture, generated and checked on 2026-09-08. The following sizes and hashes are counted from the downloadable result ZIP; they are not customer data or performance claims.

File in exampleBytesSHA-256 prefix
PROFILE.md1,1210a07acdae3e0
bundle.json2,452d055adfe11ac
input.schema.json2,06867e1cf8a0ceb
pseudolocale.json1519d797c3bb34e
release-delta.json156b87e60a96676
report.md76363e3bad6e085
witnesses.json2,9971f6885c2f239

Before you start

Does this translate my strings?

No. It compiles the messages you supply into branch fixtures; it does not translate or review wording.

Which locales are covered?

The approved en/fr subset of ICU syntax. Inputs outside that subset are not processed.

Reference material

These sources describe the surrounding formats and established tools. They do not endorse this product or prove demand for it.