[alexander-yevsyukov]

Summary

enableTestKitCoverage() now also passes io.spine.tools.gradle.testkit.coverage.home to the test JVM. The property names caches/spine-testkit under the Gradle user home, a TestKit directory shared by the worker builds of all modules.

Why:

• Today the plugin-testlib harness gives each module build/testkit-home as the Gradle user home of its TestKit worker builds. On CI that directory is empty on every run, so the first worker build of each module downloads its dependencies and generates the Gradle API JARs again.
• gradle/actions/setup-gradle saves and restores caches/ of the Gradle user home; our Windows logs show cache-includes: caches. A directory placed there is kept between runs, so a pull request run starts warm.

The plugin-testlib side, which reads the property and moves the JaCoCo agent from a gradle.properties in the TestKit directory to the command line, is SpineEventEngine/tool-base#207.

Compatibility: a plugin-testlib version that predates the property ignores it and keeps a per-module directory, so the two changes can land in either order.

Measurements

Tests of the four TestKit modules of tool-base, local, wall-clock:

TestKit home	Time
Per module, empty (every CI run today)	37 s
Shared, empty (one-time)	53 s
Shared, warm	14–16 s

Kover line and branch totals of those modules are identical with shared and per-module homes. Without the TestKit data they drop sharply (gradle-plugin-api: 13/14 lines down to 7/14), so the match shows that the worker coverage is still merged.

Worth watching after merge

• Cache size: the shared directory is about 234 MB for tool-base's worker builds. It goes into the main Gradle-home cache entry of each OS job. The repo currently uses 4.85 of 10 GB.
• First cold run: modules that start their worker builds together wait on Gradle's cache locks while the Gradle API JARs are generated. Locally that cost the one-time 53 s above. Watch the first Windows run on master for a lock timeout.
• No clean reset: the directory lives outside build/. Delete ~/.gradle/caches/spine-testkit to start from an empty one; the KDoc says so.

Test plan

• ./gradlew :buildSrc:build detekt
• In tool-base, with this buildSrc and the new plugin-testlib: tests pass, and Kover totals match per-module homes.
• Reviews: gradle-review, kotlin-engineer, review-docs. All approved; their doc findings are applied.
• After merge and a pull into tool-base: a Windows PR run restores the shared directory, and its test time drops.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-11-03T02:37:57.176069Z	1370e33	PR opened

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[Copilot]

🟢 Approved

No active review issues are recorded for the change enabling shared TestKit caches across modules and CI runs.

No open issues 🎉

What changed in this PR

Updates enableTestKitCoverage() to let compatible plugin-testlib versions share a TestKit directory across modules, enabling reuse of worker-build caches locally and across CI runs.

Changes:

• Passes io.spine.tools.gradle.testkit.coverage.home to test JVMs, pointing to caches/spine-testkit under the Gradle user home.
• Documents compatibility with older harness versions, cache persistence, and manual cleanup.

File	Description
buildSrc/​src/​main/​kotlin/​io/​spine/​gradle/​testing/​TestKitCoverage.kt	Adds the shared-directory system property and documents its behavior.

_{Review effort: Balanced}