diff --git a/lib/features/push_notification/data/keychain/keychain_sharing_manager.dart b/lib/features/push_notification/data/keychain/keychain_sharing_manager.dart
index 4b267e8ca..b6d384fdb 100644
--- a/lib/features/push_notification/data/keychain/keychain_sharing_manager.dart
+++ b/lib/features/push_notification/data/keychain/keychain_sharing_manager.dart
@@ -11,7 +11,7 @@ class KeychainSharingManager {
 
   KeychainSharingManager(this._secureStorage);
 
-  Future save(KeychainSharingSession keychainSharingSession) => _secureStorage.write(
+  Future<void> save(KeychainSharingSession keychainSharingSession) => _secureStorage.write(
     key: keychainSharingSession.accountId.asString,
     value: jsonEncode(keychainSharingSession.toJson()),
   );
@@ -28,7 +28,7 @@ class KeychainSharingManager {
     }
   }
 
-  Future delete({String? accountId}) {
+  Future<void> delete({String? accountId}) {
     if (accountId != null) {
       return _secureStorage.delete(key: accountId);
     } else {
diff --git a/test/features/push_notification/data/keychain/keychain_sharing_manager_test.dart b/test/features/push_notification/data/keychain/keychain_sharing_manager_test.dart
new file mode 100644
index 000000000..152bc73d5
--- /dev/null
+++ b/test/features/push_notification/data/keychain/keychain_sharing_manager_test.dart
@@ -0,0 +1,93 @@
+import 'dart:convert';
+
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:jmap_dart_client/jmap/account_id.dart';
+import 'package:jmap_dart_client/jmap/core/id.dart';
+import 'package:jmap_dart_client/jmap/core/user_name.dart';
+import 'package:model/model.dart';
+import 'package:tmail_ui_user/features/push_notification/data/keychain/keychain_sharing_manager.dart';
+import 'package:tmail_ui_user/features/push_notification/data/keychain/keychain_sharing_session.dart';
+
+void main() {
+  late KeychainSharingManager keychainSharingManager;
+  late FlutterSecureStorage flutterSecureStorage;
+
+  group('KeychainSharingManager:save for the same accountId', () {
+    setUp(() {
+      flutterSecureStorage = const FlutterSecureStorage();
+      keychainSharingManager = KeychainSharingManager(flutterSecureStorage);
+    });
+
+    test('WHEN keychain have no session \n'
+      'AND another session saved to keychain \n'
+      'THEN keychain will have only new session', () async {
+      // arrange
+      final keychainSharingSession = KeychainSharingSession(
+        accountId: AccountId(Id(
+            'ae08b34da40b48f30ec0b94db05675894262fbc5c2e278644f9517aaf25e8246')),
+        userName: UserName('username@domain.com'),
+        authenticationType: AuthenticationType.oidc,
+        apiUrl: 'https://jmap.domain.com/oidc/jmap',
+      );
+
+      FlutterSecureStorage.setMockInitialValues({
+        keychainSharingSession.accountId.asString: jsonEncode(keychainSharingSession.toJson())
+      });
+
+      // act
+      await keychainSharingManager.save(keychainSharingSession);
+
+      // assert
+      final keychainSession = await keychainSharingManager.getSharingSession(AccountId(Id(
+          'ae08b34da40b48f30ec0b94db05675894262fbc5c2e278644f9517aaf25e8246')));
+      expect(keychainSession, isNotNull);
+    });
+
+    test('WHEN keychain have session \n'
+        'AND another session saved to keychain \n'
+        'THEN keychain will have only new session', () async {
+      // arrange
+      final keychainSharingSession1 = KeychainSharingSession(
+        accountId: AccountId(Id(
+            'ae08b34da40b48f30ec0b94db05675894262fbc5c2e278644f9517aaf25e8246')),
+        userName: UserName('username@domain.com'),
+        authenticationType: AuthenticationType.oidc,
+        apiUrl: 'https://jmap.domain.com/oidc/jmap',
+      );
+
+      FlutterSecureStorage.setMockInitialValues({
+        keychainSharingSession1.accountId.asString: jsonEncode(keychainSharingSession1.toJson())
+      });
+
+      final keychainSharingSession2 = KeychainSharingSession(
+        accountId: AccountId(Id(
+            'ae08b34da40b48f30ec0b94db05675894262fbc5c2e278644f9517aaf25e8246')),
+        userName: UserName('username@domain.com'),
+        authenticationType: AuthenticationType.oidc,
+        apiUrl: 'https://jmap.domain.com/oidc/jmap',
+        tokenEndpoint: 'https://jmap.domain.com/oidc/jmap',
+        oidcScopes: ['email'],
+        emailState: 'ae08b34da40b48f30ec0b94',
+        tokenOIDC: TokenOIDC(
+          'ae08b34da40b48f30ec0b94',
+          TokenId('ae08b34da40b48f30ec0b94'),
+          'ae08b34da40b48f30ec0b94',
+          expiredTime: DateTime.now()
+        )
+      );
+
+      // act
+      await keychainSharingManager.save(keychainSharingSession2);
+
+      // assert
+      final keychainSession = await keychainSharingManager.getSharingSession(AccountId(Id(
+          'ae08b34da40b48f30ec0b94db05675894262fbc5c2e278644f9517aaf25e8246')));
+      expect(keychainSession, isNotNull);
+      expect(keychainSession?.tokenOIDC, isNotNull);
+      expect(keychainSession?.emailState, equals('ae08b34da40b48f30ec0b94'));
+      expect(keychainSession?.tokenEndpoint, equals('https://jmap.domain.com/oidc/jmap',));
+      expect(keychainSession?.oidcScopes, equals(['email']));
+    });
+  });
+}