Fix phonebook refresh flicker and duplicate Android recent tasks

test/device_contact_names_refresh_test.dart

@@ -0,0 +1,88 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_contacts/flutter_contacts.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:ikar/backend/modules/messages.dart';
+import 'package:ikar/core/config/app_phonebook_names.dart';
+import 'package:ikar/core/contacts/device_contacts_service.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+const phone = 79000000007;
+const channel = MethodChannel('github.com/QuisApp/flutter_contacts');
+
+List<Map<String, dynamic>> book(String name) => [
+  Contact(id: '7', displayName: name, phones: [Phone('+79000000007')]).toJson(),
+];
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  late Future<List<Map<String, dynamic>>> Function() read;
+  setUp(() {
+    SharedPreferences.setMockInitialValues({});
+    ContactCache.resetMemoryForTesting();
+    DeviceContactsService.resetMemoryForTesting();
+    AppPhonebookNames.current.value = true;
+    read = () async => book('Имя из контактов');
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(channel, (call) {
+          expect(call.method, 'select');
+          return read();
+        });
+    ContactCache.putPhone(7, phone);
+    ContactCache.put(7, 'Серверное имя');
+  });
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
+        .setMockMethodCallHandler(channel, null);
+    ContactCache.resetMemoryForTesting();
+    DeviceContactsService.resetMemoryForTesting();
+  });
+
+  testWidgets('chat name stays local throughout a delayed phonebook refresh', (
+    tester,
+  ) async {
+    expect(await DeviceContactsService.readBookForTesting(), isTrue);
+    final pending = Completer<List<Map<String, dynamic>>>();
+    read = () => pending.future;
+    final refresh = DeviceContactsService.readBookForTesting();
+    await tester.pump();
+    // A server response and widget rebuild arrive while the native reader waits.
+    ContactCache.put(7, 'Обновлённое серверное имя');
+    await tester.pumpWidget(MaterialApp(home: Text(ContactCache.get(7)!)));
+    expect(find.text('Имя из контактов'), findsOneWidget);
+    expect(DeviceContactsService.isLoaded, isTrue);
+    expect(DeviceContactsService.phonebook['+79000000007'], 'Имя из контактов');
+    await tester.pump(const Duration(seconds: 1));
+    expect(ContactCache.get(7), 'Имя из контактов');
+    pending.complete(book('Имя из контактов'));
+    await refresh;
+    await tester.pumpWidget(MaterialApp(home: Text(ContactCache.get(7)!)));
+    expect(find.text('Имя из контактов'), findsOneWidget);
+    expect(find.text('Обновлённое серверное имя'), findsNothing);
+    await tester.pump(const Duration(seconds: 3));
+    expect(ContactCache.get(7), 'Имя из контактов');
+  });
+
+  test('a failed refresh keeps the last successfully loaded names', () async {
+    await DeviceContactsService.readBookForTesting();
+    read = () async => throw PlatformException(code: 'READ_FAILED');
+    expect(await DeviceContactsService.readBookForTesting(), isFalse);
+    expect(ContactCache.get(7), 'Имя из контактов');
+    expect(DeviceContactsService.isLoaded, isTrue);
+    expect(DeviceContactsService.knownNumbers, 1);
+  });
+
+  test('a successful refresh applies renamed and deleted contacts', () async {
+    await DeviceContactsService.readBookForTesting();
+    read = () async => book('Новое имя');
+    expect(await DeviceContactsService.readBookForTesting(), isTrue);
+    expect(ContactCache.get(7), 'Новое имя');
+    read = () async => [];
+    expect(await DeviceContactsService.readBookForTesting(), isTrue);
+    expect(DeviceContactsService.knownNumbers, 0);
+    expect(DeviceContactsService.phonebook, isEmpty);
+    expect(ContactCache.get(7), 'Серверное имя');
+  });
+}