werkator/docs/prs/2026-10-10-PR#144-tests-in-one-locale.md

PR#144: Tests in One Locale

WARNING: This document describes only the change applied in this PR. It may already be outdated once the next PR is merged. Historic PR-documentation is not maintained along with new PRs — treat it as a snapshot, not as current documentation.

The Problem

The tests ran in whatever locale the host had, and so did the processes they start, bash and git among them. On a host with a German LC_NUMERIC, bash writes EPOCHREALTIME as 1791625756,465101; $((…)) reads the comma as its comma operator. That made a test of PR#143 fail locally, while it would have passed on another host.

Non-Goals

• No change to the locale of Werkator itself or of the builds it runs.

The Scenarios

Scenario#144.01: Tests run in the US English locale

• Given a host with another locale, e.g. a German LC_NUMERIC
• When a test runs, under Gradle or under PIT
• Then the test and the processes it starts use en_US.UTF-8
• So that a test that formats or parses numbers, dates or messages behaves the same on every host.

Verified by

• TestLocaleIntegrationTest

The Solution

• Every Test task sets LANG and LC_ALL to en_US.UTF-8, and user.language and user.country to en and US.
• The pitest task sets the same environment for its main process; PIT's test processes inherit it.