[tests] Fail fast when the emulator package manager service is wedged

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/DeviceTest.cs

@@ -69,6 +69,59 @@ public void AssertHasDevices (bool fail = true)
 			}
 		}
 
+		/// <summary>
+		/// Probes the Android package manager service the same way `bundletool build-apks
+		/// --connected-device` (which runs `pm list features`) and `adb install` do. On CI the
+		/// emulator's system_server sometimes wedges while `adb shell echo OK` still succeeds, so
+		/// <see cref="IsDeviceAttached"/> reports the device as healthy even though every subsequent
+		/// build/install fails deep inside a test with a cryptic
+		/// "Failure calling service package: Broken pipe" (XABAS0000). Retries a few times so a
+		/// momentary hiccup does not trigger an unnecessary emulator restart.
+		/// </summary>
+		protected static bool IsPackageManagerResponsive (out string diagnostic)
+		{
+			string output = "";
+			for (int attempt = 0; attempt < 3; attempt++) {
+				output = (RunAdbCommand ("shell pm list features", timeout: 30) ?? "").Trim ();
+				bool broken = output.Contains ("Failure calling service", StringComparison.OrdinalIgnoreCase) ||
+					output.Contains ("Broken pipe", StringComparison.OrdinalIgnoreCase) ||
+					output.Contains ("Can't find service", StringComparison.OrdinalIgnoreCase);
+				// A responsive package service always lists the framework's own features.
+				if (!broken && output.Contains ("feature:", StringComparison.OrdinalIgnoreCase)) {
+					diagnostic = output;
+					return true;
+				}
+				WaitFor ((int) TimeSpan.FromSeconds (2).TotalMilliseconds);
+			}
+			diagnostic = output;
+			return false;
+		}
+
+		/// <summary>
+		/// Fails fast, with a clear reason, when the emulator's package manager service is
+		/// unusable — instead of letting the app build/install fail cryptically later and
+		/// reporting an emulator crash as N unrelated test failures. Attempts one emulator
+		/// restart first; if the service is still broken the run is marked inconclusive
+		/// (an infrastructure problem, not a product regression).
+		/// </summary>
+		protected void AssertPackageManagerResponsive ()
+		{
+			if (IsPackageManagerResponsive (out _)) {
+				return;
+			}
+
+			TestContext.Out.WriteLine ("Android package manager service is unresponsive; restarting the emulator.");
+			RestartDevice ();
+			AssertHasDevices ();
+
+			if (!IsPackageManagerResponsive (out string diagnostic)) {
+				Assert.Inconclusive (
+					"Android package manager service is unresponsive even after restarting the emulator " +
+					"(system_server likely crashed). Skipping so an emulator failure is not reported as a test failure. " +
+					$"Last 'adb shell pm list features' output: {diagnostic}");
+			}
+		}
+
 		[OneTimeSetUp]
 		public void DeviceSetup ()
 		{
@@ -126,6 +179,11 @@ public virtual void SetupTest ()
 				AssertHasDevices ();
 			}
 
+			// `adb shell echo OK` can succeed while the package manager service is wedged, so
+			// verify it is responsive before a test wastes time building/installing an app that
+			// would otherwise fail with a cryptic "Failure calling service package" error.
+			AssertPackageManagerResponsive ();
+
 			// We want to start with a clean logcat buffer for each test
 			ClearAdbLogcat ();
 		}