test: add end-to-end demo smoke test

[kikoso]

Summary

Adds an end-to-end smoke test for the demo app, so a broken demo is caught in CI instead of by users.

• DemoSmokeTest (parameterized, one case per demo): starts MainActivity, opens the demo through the menu, waits for its map, zooms out and back in (which exercises the camera-idle path clustering and renderers hook into), checks the demo is still in the foreground, and navigates back. The two Street View demos have no map and are only checked for staying open.
• DemoCatalogTest: fails if a demo activity is declared in the manifest but missing from the menu (or the other way round), so new demos added to demoGroups() are covered automatically.
• Android Test Orchestrator: each test runs in its own process, so a crashing demo fails only its own case instead of aborting the run.
• Demo smoke test workflow: runs the suite on an API 36 emulator with ACTIONS_API_KEY and requireMapLoaded=true. Skips with a notice when the secret is not available (forks, Dependabot).

Supporting changes: the demo list moved to a top-level demoGroups() in MainActivity.kt, menu rows got test tags, and AGENTS.md documents how to run it.

Notes

• Without a Maps API key in a valid format the demos close themselves. A failed assumeTrue is reported as a failure by the test platform here, so instead the test generates no cases and logs a warning.
• Gradle's class= runner argument only ran the first class of a comma-separated list, so the tests live in a smoke package and are filtered by package.
• The workflow uses API 36. Emulators never update Google Play services, and API 34 images bundle 23.18, where adding advanced markers crashes inside Play services. API 36 bundles 25.26, which works.

Found by the test

The first CI runs with a real key caught two demo bugs, fixed here:

• The demo manifest did not declare org.apache.http.legacy, which the Maps SDK needs when targeting API 28+ on devices with older Play services. 25 demos crashed with NoClassDefFoundError: org/apache/http/ProtocolVersion. The compose demo already declares it.
• PolylineProgressDemoActivity called newLatLngBounds before the map was laid out ("Map size can't be 0"), which shows up on slower devices. It now waits for layout.

Testing

CI: Demo smoke test passes, 29/29 with ACTIONS_API_KEY and requireMapLoaded=true.

On a local API 34 emulator with a fake key in a valid format:

• DemoCatalogTest 1/1 and DemoSmokeTest 28/28 pass (about 2:45).
• With a crash injected into ClusteringDemoActivity, only that case failed and the other 27 still ran.
• :demo:lintStandardDebug and :demo:testStandardDebugUnitTest pass.

Run locally with:

./gradlew :demo:connectedStandardDebugAndroidTest \
  -Pandroid.testInstrumentationRunnerArguments.package=com.google.maps.android.utils.demo.smoke

[googlemaps-bot]

Code Coverage

Overall Project	56.95%	🍏

There is no coverage information present for the Files changed

[dkhawk]

Overall this is fantastic work, @kikoso! Bringing end-to-end smoke testing under Android Test Orchestrator with DemoCatalogTest keeping the manifest and menu in sync is a huge reliability win for the repo. The fact that it already caught the legacy Apache HTTP dependency and the polyline bounds layout race proves its value immediately.

A couple of minor suggestions:

1. LazyColumn scroll on group headers: In DemoSmokeTest.kt, consider adding .performScrollTo() before .performClick() on the group header as well (composeRule.onNodeWithTag(groupTestTag(group)).performScrollTo().performClick()). Since DemoList uses LazyColumn, on smaller screens or landscape mode, headers near the bottom (like Street View) might not be composed yet when clicked.
2. Post-merge CI on main: Consider adding push: branches: [main] to .github/workflows/demo-smoke-test.yml so that post-merge commits and automated bot bumps to main are validated too.

LGTM! 🚀