fix(auth): show the Plex sign-in QR in the app on a car

Signing in opened plex.tv in a browser, and a head unit has none: the user was left staring at a launcher error with no way to link the account. The QR code and the linking code are now rendered in the app on a car, so the pairing happens on a phone while the vehicle shows what to scan.
2026-08-06 03:45:09 +02:00
parent 961e9c0326
commit f63a4b039a
2 changed files with 159 additions and 5 deletions
@@ -0,0 +1,133 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:http/testing.dart';
+import 'package:http/http.dart' as http;
+import 'package:plezy/i18n/strings.g.dart';
+import 'package:plezy/screens/auth/plex_pin_auth_flow.dart';
+import 'package:plezy/services/plex_auth_service.dart';
+import 'package:plezy/utils/media_server_http_client.dart';
+import 'package:plezy/utils/platform_detector.dart';
+import 'package:qr_flutter/qr_flutter.dart';
+
+import '../../test_helpers/theme.dart';
+
+/// Serves a PIN without touching plex.tv, and never resolves the claim poll so
+/// the flow parks on whichever waiting UI it chose.
+class _StalledPlexAuthService extends PlexAuthService {
+  _StalledPlexAuthService()
+    : super.forTesting(http: MediaServerHttpClient(client: MockClient((_) async => http.Response('{}', 200))));
+
+  @override
+  Future<Map<String, dynamic>> createPin() async => <String, dynamic>{'id': 1, 'code': 'ABCD'};
+
+  @override
+  String getAuthUrl(String pinCode) => 'https://app.plex.tv/auth#?code=$pinCode';
+
+  @override
+  Future<String?> pollPinUntilClaimed(
+    int pinId, {
+    Duration timeout = const Duration(minutes: 2),
+    bool Function()? shouldCancel,
+  }) => Completer<String?>().future;
+}
+
+/// The channel every `url_launcher` platform implementation talks to; a
+/// recorded call means the flow tried to leave the app for a browser.
+const _urlLauncherChannel = MethodChannel('plugins.flutter.io/url_launcher');
+
+void main() {
+  final launched = <String>[];
+
+  setUpAll(() => LocaleSettings.setLocaleSync(AppLocale.en));
+
+  setUp(() {
+    launched.clear();
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMethodCallHandler(_urlLauncherChannel, (
+      call,
+    ) async {
+      switch (call.method) {
+        case 'launch':
+          launched.add((call.arguments as Map)['url'] as String);
+          return true;
+        case 'canLaunch':
+          return true;
+        default:
+          return null;
+      }
+    });
+  });
+
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMethodCallHandler(
+      _urlLauncherChannel,
+      null,
+    );
+    TvDetectionService.debugSetAutomotiveOverride(null);
+    TvDetectionService.debugReset();
+  });
+
+  Future<void> pumpFlow(WidgetTester tester) async {
+    await tester.pumpWidget(
+      TranslationProvider(
+        child: MaterialApp(
+          theme: ThemeData(extensions: const [testMonoTokens]),
+          home: Scaffold(
+            body: PlexPinAuthFlow(
+              onTokenReceived: (_) async {},
+              autoStartQrOnTV: false,
+              serviceFactory: () async => _StalledPlexAuthService(),
+            ),
+          ),
+        ),
+      ),
+    );
+    await tester.pump();
+    await tester.pump();
+  }
+
+  testWidgets('a car keeps the Plex hand-off in-app as a QR code', (tester) async {
+    // A head unit has no browser: Android Automotive gives an app-launched URL
+    // to the car link viewer, so launching one strands the flow on a spinner
+    // until the PIN expires.
+    TvDetectionService.debugSetAutomotiveOverride(true);
+    await pumpFlow(tester);
+
+    await tester.tap(find.text(t.auth.signInWithPlex));
+    await tester.pump();
+    await tester.pump();
+
+    expect(find.byType(QrImageView), findsOneWidget);
+    expect(find.text(t.auth.scanQRToSignIn), findsOneWidget);
+    expect(find.text(t.auth.waitingForAuth), findsNothing);
+    expect(launched, isEmpty);
+  });
+
+  testWidgets('every other device still hands Plex sign-in to a browser', (tester) async {
+    TvDetectionService.debugSetAutomotiveOverride(false);
+    await pumpFlow(tester);
+
+    await tester.tap(find.text(t.auth.signInWithPlex));
+    await tester.pump();
+    await tester.pump();
+
+    expect(launched, hasLength(1));
+    expect(launched.single, startsWith('https://app.plex.tv/auth'));
+    expect(find.text(t.auth.waitingForAuth), findsOneWidget);
+    expect(find.byType(QrImageView), findsNothing);
+  });
+
+  testWidgets('the QR button is unaffected off a car', (tester) async {
+    TvDetectionService.debugSetAutomotiveOverride(false);
+    await pumpFlow(tester);
+
+    await tester.tap(find.text(t.auth.showQRCode));
+    await tester.pump();
+    await tester.pump();
+
+    expect(find.byType(QrImageView), findsOneWidget);
+    expect(launched, isEmpty);
+  });
+}