[task] document update smoke workflow

Author: wslany

automationScripts/update-smoke/README.md

@@ -0,0 +1,49 @@
+# Catroid Update Smoke Test
+
+This smoke test exercises the update path users take from the currently deployed
+Play Store branch to the APK under test.
+
+The workflow builds a release-style baseline APK from `main`, and a
+release-style `updateTest` APK for the PR with the same package
+name and a higher version code. Both APKs are built locally and signed with the
+same debug key so Android accepts the in-place update. The `updateTest` build
+type is not suitable for updating over an APK actually downloaded from Google
+Play, because Play-signed and debug-signed APKs cannot update each other.
+
+## Local Run
+
+Build or provide two APKs with the same package name, where the second APK has a
+higher version code:
+
+```sh
+ADB=/path/to/adb \
+automationScripts/update-smoke/run-update-smoke.sh \
+  /path/to/baseline.apk \
+  /path/to/pr.apk \
+  org.catrobat.catroid
+```
+
+The emulator must allow `adb root`, because the test seeds private app storage
+under `/data/data/org.catrobat.catroid` before launching the updated APK.
+
+## Seeded Fixtures
+
+The script seeds:
+
+- `Pong Starter` as a known-good project.
+- `UpdateSmokeBrokenProject` with malformed `code.xml` and a corrupt thumbnail.
+- `fixtures/legacy-room-v2-app-database.sql`, a Room schema version 2 database
+  fixture whose `project_response` table intentionally lacks the version 3
+  `private` column.
+
+## Environment Variables
+
+- `ADB`: path to `adb`; defaults to `adb`.
+- `UPDATE_SMOKE_ARTIFACT_DIR`: directory for logcat/UI artifacts.
+- `UPDATE_SMOKE_GOOD_PROJECT_ARCHIVE`: override the good `.catrobat` fixture.
+- `UPDATE_SMOKE_GOOD_PROJECT_NAME`: expected display name for the good project.
+- `UPDATE_SMOKE_BROKEN_PROJECT_NAME`: expected display name for the broken project.
+- `UPDATE_SMOKE_LEGACY_DB_SQL`: override the legacy Room SQL fixture.
+- `UPDATE_SMOKE_SEED_LEGACY_DB`: set to `false` to skip DB seeding.
+- `UPDATE_SMOKE_STRICT_UI`: defaults to `true`; set to `false` for local
+  debugging when UI matching should not fail the run.