Fix the algorithm counting the package failures

Use the sliding window algorithm to detect if there exists a window
containing failures equal to or above the trigger threshold.

Bug: 140841942
Test: atest PackageWatchdogTest
Change-Id: I34a20e4d3b98a093dffa05fc7c7c026905834b53

1 files changed, 33 insertions, 0 deletions

diff --git a/tests/PackageWatchdog/src/com/android/server/PackageWatchdogTest.java b/tests/PackageWatchdog/src/com/android/server/PackageWatchdogTest.java
index ab31ed7389a3..ff4c9702bd80 100644
--- a/tests/PackageWatchdog/src/com/android/server/PackageWatchdogTest.java
+++ b/tests/PackageWatchdog/src/com/android/server/PackageWatchdogTest.java
@@ -765,6 +765,39 @@ public class PackageWatchdogTest {
         assertThat(observer.mHealthCheckFailedPackages).containsExactly(APP_B);
     }
 
+    /** Test we are notified when enough failures are triggered within any window. */
+    @Test
+    public void testFailureTriggerWindow() {
+        adoptShellPermissions(
+                Manifest.permission.WRITE_DEVICE_CONFIG,
+                Manifest.permission.READ_DEVICE_CONFIG);
+        DeviceConfig.setProperty(DeviceConfig.NAMESPACE_ROLLBACK,
+                PackageWatchdog.PROPERTY_WATCHDOG_TRIGGER_FAILURE_COUNT,
+                Integer.toString(3), /*makeDefault*/false);
+        DeviceConfig.setProperty(DeviceConfig.NAMESPACE_ROLLBACK,
+                PackageWatchdog.PROPERTY_WATCHDOG_TRIGGER_DURATION_MILLIS,
+                Integer.toString(1000), /*makeDefault*/false);
+        PackageWatchdog watchdog = createWatchdog();
+        TestObserver observer = new TestObserver(OBSERVER_NAME_1);
+
+        watchdog.startObservingHealth(observer, Arrays.asList(APP_A), Long.MAX_VALUE);
+        // Raise 2 failures at t=0 and t=900 respectively
+        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));
+        mTestLooper.dispatchAll();
+        moveTimeForwardAndDispatch(900);
+        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));
+        mTestLooper.dispatchAll();
+
+        // Raise 2 failures at t=1100
+        moveTimeForwardAndDispatch(200);
+        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));
+        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));
+        mTestLooper.dispatchAll();
+
+        // We should receive APP_A since there are 3 failures within 1000ms window
+        assertThat(observer.mHealthCheckFailedPackages).containsExactly(APP_A);
+    }
+
     private void adoptShellPermissions(String... permissions) {
         InstrumentationRegistry
                 .getInstrumentation()