test(android): Add automated coverage for GenerateSentryOptionsTask (Gradle asset generation)

[antonis]

Summary

Add automated test coverage for the Android Gradle asset-generation logic in packages/core/sentry.gradle.kts — specifically the GenerateSentryOptionsTask introduced in #6751. Today this logic is only verified manually against the sample apps; there is no automated regression protection.

Background

#6751 replaced the old copySentryJsonConfiguration copy+cleanup tasks with a typed GenerateSentryOptionsTask that generates sentry.options.json into build/generated/sentry/options/ and registers it as a generated assets source. The task owns non-trivial logic:

• Plain copy of the source sentry.options.json into the generated dir.
• SENTRY_ENVIRONMENT / SENTRY_RELEASE / SENTRY_DIST override rewriting of the JSON keys.
• Invalid-JSON fallback (copy as-is with a warning).
• Missing-source handling (leave the output dir empty).
• SENTRY_COPY_OPTIONS_FILE=false opt-out (clear the output, produce nothing).

Raised by automated review on #6751: no tests reference GenerateSentryOptionsTask / generateSentryOptions, whereas the parallel iOS path (sentry-xcode.sh) and the Metro serializer are covered.

Why this isn't a quick add

sentry.gradle.kts is a script plugin, applied by consumers via apply from: "…/sentry.gradle.kts". The task class is declared inside the script, so:

• It is not compiled into any module and cannot be imported by a test.
• The existing JUnit tests (packages/core/android/src/test/...) belong to the :sentry_react-native library module (io.sentry.react.*), a different compilation unit / classpath.
• There is no buildSrc, no GradleTestKit harness, and no standalone Gradle-plugin module. buildSrc would not help — it lives on the library's build classpath, not the consumer app's build where the script executes.

So there is no seam to unit-test the task as-is. Two viable paths, both larger than the original fix:

Option A — GradleTestKit functional test

Add a test module with gradleTestKit(), a fixture Android app that apply froms the script, run generateSentryOptions, and assert the generated file + up-to-date/caching behavior.

• Cost: requires AGP + Android SDK on the test classpath (the script reflects against the AGP variant API and runs inside com.android.application). New, slower, potentially flaky CI job.
• Upside: exercises the real wiring (generated-source registration, merge*Assets ordering) end to end, not just the pure logic.

Option B — Extract to a binary plugin + ProjectBuilder unit test

Move the task into a real compiled Gradle plugin / module so it can be imported, then unit-test the action with org.gradle.testfixtures.ProjectBuilder (no AGP needed — it's a plain DefaultTask).

• Cost: converting the script plugin to a binary plugin changes how consumers apply the SDK (apply plugin vs apply from) — a breaking integration change requiring a migration path.
• Upside: fast, isolated unit tests of the core logic; also a cleaner long-term architecture.

Cases to cover (whichever path)

• Plain copy — source present, no overrides → generated file matches source.
• SENTRY_ENVIRONMENT / SENTRY_RELEASE / SENTRY_DIST overrides rewrite the corresponding keys.
• Invalid JSON → copied as-is, warning logged, build not failed.
• Missing source file → output dir left empty, no failure.
• SENTRY_COPY_OPTIONS_FILE=false → output cleared / nothing generated (and a stale prior output is removed).
• (Option A only) generated file is merged into merge{Debug,Release}Assets and packaged; second build is UP-TO-DATE; nothing written to src/main/assets.

Recommendation

Prefer Option A for behavioral fidelity if the CI cost is acceptable; otherwise Option B as part of a broader move to a binary Gradle plugin. Track the plugin-ification separately if chosen, since it carries a consumer-facing migration.

References

• PR fix(android): Generate sentry.options.json into build folder instead of source tree #6751 — the change under test
• packages/core/sentry.gradle.kts — GenerateSentryOptionsTask (task class + wiring)
• packages/core/android/src/test/java/io/sentry/react/ — existing (library-module) JUnit tests

[linear-code]

RN-789