Resolve pending start/stop method channel futures in AppStateNotifier

packages/google_mobile_ads/android/src/main/java/io/flutter/plugins/googlemobileads/AppStateNotifier.java

@@ -64,9 +64,11 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
     switch (call.method) {
       case "start":
         start();
+        result.success(null);
         break;
       case "stop":
         stop();
+        result.success(null);
         break;
       default:
         result.notImplemented();

packages/google_mobile_ads/android/src/test/java/io/flutter/plugins/googlemobileads/AppStateNotifierTest.java

@@ -0,0 +1,73 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package io.flutter.plugins.googlemobileads;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.spy;
+
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel.Result;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Tests for {@link AppStateNotifier}. */
+@RunWith(RobolectricTestRunner.class)
+public class AppStateNotifierTest {
+
+  private AppStateNotifier appStateNotifier;
+  private BinaryMessenger mockBinaryMessenger;
+
+  @Before
+  public void setup() {
+    mockBinaryMessenger = mock(BinaryMessenger.class);
+    appStateNotifier = spy(new AppStateNotifier(mockBinaryMessenger));
+  }
+
+  @Test
+  public void onMethodCall_start() {
+    MethodCall call = new MethodCall("start", null);
+    Result mockResult = mock(Result.class);
+
+    appStateNotifier.onMethodCall(call, mockResult);
+
+    verify(appStateNotifier).start();
+    verify(mockResult).success(null);
+  }
+
+  @Test
+  public void onMethodCall_stop() {
+    MethodCall call = new MethodCall("stop", null);
+    Result mockResult = mock(Result.class);
+
+    appStateNotifier.onMethodCall(call, mockResult);
+
+    verify(appStateNotifier).stop();
+    verify(mockResult).success(null);
+  }
+
+  @Test
+  public void onMethodCall_unknownMethod() {
+    MethodCall call = new MethodCall("unknown", null);
+    Result mockResult = mock(Result.class);
+
+    appStateNotifier.onMethodCall(call, mockResult);
+
+    verify(mockResult).notImplemented();
+  }
+}