diff --git a/lib/data/volume_events_service.dart b/lib/data/volume_events_service.dart
index d57936a..360de75 100644
--- a/lib/data/volume_events_service.dart
+++ b/lib/data/volume_events_service.dart
@@ -3,7 +3,7 @@ import 'package:flutter/services.dart';
 import 'package:platform/platform.dart';
 
 class VolumeEventsService {
-  final LocalPlatform localPlatform;
+  final LocalPlatform _localPlatform;
 
   @visibleForTesting
   static const volumeHandlingChannel = MethodChannel("com.vodemn.lightmeter/volumeHandling");
@@ -11,12 +11,12 @@ class VolumeEventsService {
   @visibleForTesting
   static const volumeEventsChannel = EventChannel("com.vodemn.lightmeter/volumeEvents");
 
-  const VolumeEventsService(this.localPlatform);
+  const VolumeEventsService(this._localPlatform);
 
   /// If set to `false` we allow system to handle key events.
   /// Returns current status of volume handling.
   Future<bool> setVolumeHandling(bool enableHandling) async {
-    if (!localPlatform.isAndroid) {
+    if (!_localPlatform.isAndroid) {
       return false;
     }
     return volumeHandlingChannel
@@ -29,7 +29,7 @@ class VolumeEventsService {
   /// KEYCODE_VOLUME_DOWN = 25;
   /// pressed
   Stream<int> volumeButtonsEventStream() {
-    if (!localPlatform.isAndroid) {
+    if (!_localPlatform.isAndroid) {
       return const Stream.empty();
     }
     return volumeEventsChannel
diff --git a/lib/screens/metering/bloc_metering.dart b/lib/screens/metering/bloc_metering.dart
index cbb0356..753a7e7 100644
--- a/lib/screens/metering/bloc_metering.dart
+++ b/lib/screens/metering/bloc_metering.dart
@@ -10,9 +10,9 @@ import 'package:lightmeter/screens/metering/communication/event_communication_me
     as communication_events;
 import 'package:lightmeter/screens/metering/communication/state_communication_metering.dart'
     as communication_states;
-import 'package:lightmeter/screens/metering/components/shared/volume_keys_notifier/notifier_volume_keys.dart';
 import 'package:lightmeter/screens/metering/event_metering.dart';
 import 'package:lightmeter/screens/metering/state_metering.dart';
+import 'package:lightmeter/screens/metering/utils/notifier_volume_keys.dart';
 import 'package:m3_lightmeter_resources/m3_lightmeter_resources.dart';
 
 class MeteringBloc extends Bloc<MeteringEvent, MeteringState> {
diff --git a/lib/screens/metering/flow_metering.dart b/lib/screens/metering/flow_metering.dart
index cca5675..f78482d 100644
--- a/lib/screens/metering/flow_metering.dart
+++ b/lib/screens/metering/flow_metering.dart
@@ -4,8 +4,8 @@ import 'package:lightmeter/interactors/metering_interactor.dart';
 import 'package:lightmeter/providers/services_provider.dart';
 import 'package:lightmeter/screens/metering/bloc_metering.dart';
 import 'package:lightmeter/screens/metering/communication/bloc_communication_metering.dart';
-import 'package:lightmeter/screens/metering/components/shared/volume_keys_notifier/notifier_volume_keys.dart';
 import 'package:lightmeter/screens/metering/screen_metering.dart';
+import 'package:lightmeter/screens/metering/utils/notifier_volume_keys.dart';
 
 class MeteringFlow extends StatefulWidget {
   const MeteringFlow({super.key});
diff --git a/lib/screens/metering/components/shared/volume_keys_notifier/notifier_volume_keys.dart b/lib/screens/metering/utils/notifier_volume_keys.dart
similarity index 82%
rename from lib/screens/metering/components/shared/volume_keys_notifier/notifier_volume_keys.dart
rename to lib/screens/metering/utils/notifier_volume_keys.dart
index df64fdf..0c19955 100644
--- a/lib/screens/metering/components/shared/volume_keys_notifier/notifier_volume_keys.dart
+++ b/lib/screens/metering/utils/notifier_volume_keys.dart
@@ -5,12 +5,12 @@ import 'package:lightmeter/data/models/volume_action.dart';
 import 'package:lightmeter/data/volume_events_service.dart';
 
 class VolumeKeysNotifier extends ChangeNotifier with RouteAware {
-  final VolumeEventsService volumeEventsService;
+  final VolumeEventsService _volumeEventsService;
   late final StreamSubscription<VolumeKey> _volumeKeysSubscription;
   VolumeKey _value = VolumeKey.up;
 
-  VolumeKeysNotifier(this.volumeEventsService) {
-    _volumeKeysSubscription = volumeEventsService
+  VolumeKeysNotifier(this._volumeEventsService) {
+    _volumeKeysSubscription = _volumeEventsService
         .volumeButtonsEventStream()
         .map((event) => event == 24 ? VolumeKey.up : VolumeKey.down)
         .listen((event) {
@@ -19,6 +19,8 @@ class VolumeKeysNotifier extends ChangeNotifier with RouteAware {
   }
 
   VolumeKey get value => _value;
+
+  @protected
   set value(VolumeKey newValue) {
     _value = newValue;
     notifyListeners();
diff --git a/test/screens/metering/utils/notifier_volume_keys_test.dart b/test/screens/metering/utils/notifier_volume_keys_test.dart
new file mode 100644
index 0000000..47332c8
--- /dev/null
+++ b/test/screens/metering/utils/notifier_volume_keys_test.dart
@@ -0,0 +1,50 @@
+import 'dart:async';
+
+import 'package:lightmeter/data/models/volume_action.dart';
+import 'package:lightmeter/data/volume_events_service.dart';
+import 'package:lightmeter/screens/metering/utils/notifier_volume_keys.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:test/test.dart';
+
+class _MockVolumeEventsService extends Mock implements VolumeEventsService {}
+
+class _ValueChanged {
+  void onChanged(VolumeKey value) {}
+}
+
+class _MockValueChanged extends Mock implements _ValueChanged {}
+
+void main() {
+  late _MockVolumeEventsService mockVolumeEventsService;
+
+  setUp(() {
+    mockVolumeEventsService = _MockVolumeEventsService();
+  });
+
+  test(
+    'Listen to `volumeButtonsEventStream()`',
+    () async {
+      final StreamController<int> volumeButtonsEvents = StreamController<int>();
+      when(() => mockVolumeEventsService.volumeButtonsEventStream()).thenAnswer((_) => volumeButtonsEvents.stream);
+
+      final volumeKeysNotifier = VolumeKeysNotifier(mockVolumeEventsService);
+      final functions = _MockValueChanged();
+      volumeKeysNotifier.addListener(() => functions.onChanged(volumeKeysNotifier.value));
+      expect(volumeKeysNotifier.value, VolumeKey.up);
+
+      volumeButtonsEvents.add(25);
+      volumeButtonsEvents.add(25);
+      volumeButtonsEvents.add(25);
+      volumeButtonsEvents.add(24);
+      volumeButtonsEvents.add(24);
+      volumeButtonsEvents.add(25);
+      await Future.delayed(Duration.zero);
+      verify(() => functions.onChanged(VolumeKey.up)).called(2);
+      verify(() => functions.onChanged(VolumeKey.down)).called(4);
+
+      volumeKeysNotifier.removeListener(() => functions.onChanged(volumeKeysNotifier.value));
+      await volumeKeysNotifier.dispose();
+      await volumeButtonsEvents.close();
+    },
+  );
+}