From 99a40a09e76a9732859e36a21f00992c7b259751 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Enrique=20Lo=CC=81pez=20Man=CC=83as?=
 <eenriquelopez@gmail.com>
Date: Tue, 3 Nov 2026 12:17:51 +0100
Subject: [PATCH] test: log uncaught exceptions in the demo smoke tests

The smoke tests replace the default uncaught exception handler with one that
only records the exception. If the main thread throws, the app hangs instead of
crashing and the test may never reach assertNoUncaughtExceptions(), so the
exception was lost. Log it under the DemoSmokeTest tag as well.

Also note in AGENTS.md to keep the screen on when running the emulator suites
on a physical device: a screen timeout in the middle of a run made the demo app
hang with an ANR (#1070).
---
 AGENTS.md                                                 | 7 +++++++
 .../google/maps/android/compose/smoke/DemoAppSmokeTest.kt | 8 +++++++-
 .../maps/android/compose/smoke/DemoMenuNavigationTest.kt  | 8 +++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/AGENTS.md b/AGENTS.md
index a9346413..5f1900e1 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -76,6 +76,13 @@ and they are covered automatically. To run them with a device or emulator attach
 Add `-Pandroid.testInstrumentationRunnerArguments.requireMapLoaded=true` to also
 wait for map tiles to render, which needs a real key.
 
+On a physical device, keep the screen on for the whole run (for example
+`adb shell svc power stayon usb`, and `adb shell svc power stayon false`
+afterwards). If the screen times out in the middle, a demo can stop resuming and
+the run hangs with an ANR instead of failing (see #1070). The smoke tests also
+log any uncaught exception under the `DemoSmokeTest` tag, so check logcat if a
+run hangs.
+
 Running `maps-app` requires a Maps API key: put `MAPS_API_KEY=...` in
 `secrets.properties` at the repo root (see `local.defaults.properties` for the
 template). Never hardcode or commit API keys.
diff --git a/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoAppSmokeTest.kt b/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoAppSmokeTest.kt
index 7e01bb86..46649021 100644
--- a/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoAppSmokeTest.kt
+++ b/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoAppSmokeTest.kt
@@ -17,6 +17,7 @@
 package com.google.maps.android.compose.smoke
 
 import android.graphics.Rect
+import android.util.Log
 import android.view.View
 import android.view.ViewGroup
 import androidx.activity.ComponentActivity
@@ -115,7 +116,10 @@ class DemoAppSmokeTest(private val demoName: String, private val demoActivity: C
         assumeTrue("Maps API key not specified", hasValidApiKey)
 
         defaultHandler = Thread.getDefaultUncaughtExceptionHandler()
-        Thread.setDefaultUncaughtExceptionHandler { _, throwable ->
+        Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
+            // Log it: if the main thread dies here the app hangs and the test may never reach
+            // assertNoUncaughtExceptions(), so logcat is the only place it would show up.
+            Log.e(TAG, "Uncaught exception on thread ${thread.name}", throwable)
             uncaughtExceptions.add(throwable)
         }
     }
@@ -270,3 +274,5 @@ class DemoAppSmokeTest(private val demoName: String, private val demoActivity: C
         walk(this@mapSurfaces)
     }
 }
+
+private const val TAG = "DemoSmokeTest"
diff --git a/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoMenuNavigationTest.kt b/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoMenuNavigationTest.kt
index 165c7955..3811182a 100644
--- a/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoMenuNavigationTest.kt
+++ b/maps-app/src/androidTest/java/com/google/maps/android/compose/smoke/DemoMenuNavigationTest.kt
@@ -18,6 +18,7 @@ package com.google.maps.android.compose.smoke
 
 import android.app.Activity
 import android.os.SystemClock
+import android.util.Log
 import android.view.View
 import android.view.ViewGroup
 import androidx.compose.ui.test.hasScrollToIndexAction
@@ -77,7 +78,10 @@ class DemoMenuNavigationTest(
     @Before
     fun setUp() {
         defaultHandler = Thread.getDefaultUncaughtExceptionHandler()
-        Thread.setDefaultUncaughtExceptionHandler { _, throwable ->
+        Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
+            // Log it: if the main thread dies here the app hangs and the test may never reach
+            // assertNoUncaughtExceptions(), so logcat is the only place it would show up.
+            Log.e(TAG, "Uncaught exception on thread ${thread.name}", throwable)
             uncaughtExceptions.add(throwable)
         }
     }
@@ -209,3 +213,5 @@ class DemoMenuNavigationTest(
         }
     }
 }
+
+private const val TAG = "DemoSmokeTest"