fix(ios): scan app documents without the Files folder picker

test/ios_library_folder_sheet_test.dart

@@ -0,0 +1,138 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:spotiflac_android/l10n/l10n.dart';
+import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/theme/mornye_theme.dart';
+import 'package:spotiflac_android/widgets/ios_library_folder_sheet.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  const backend = MethodChannel('com.zarz.spotiflac/backend');
+  const paths = MethodChannel('plugins.flutter.io/path_provider');
+  final messenger =
+      TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger;
+  late Directory root;
+  late Directory documents;
+  late List<String> calls;
+  IosPickedDirectory? selection;
+  Object? failure;
+
+  setUp(() async {
+    root = await Directory.systemTemp.createTemp('ios-library-picker-');
+    documents = Directory('${root.path}/Documents');
+    calls = [];
+    selection = null;
+    failure = null;
+    messenger.setMockMethodCallHandler(paths, (_) async => documents.path);
+    messenger.setMockMethodCallHandler(backend, (call) async {
+      calls.add(call.method);
+      return {'path': '/external/Music', 'bookmark': 'granted-folder-bookmark'};
+    });
+  });
+  tearDown(() async {
+    messenger.setMockMethodCallHandler(paths, null);
+    messenger.setMockMethodCallHandler(backend, null);
+    await root.delete(recursive: true);
+  });
+
+  Future<void> openSheet(WidgetTester tester, {bool mornye = false}) async {
+    await tester.pumpWidget(
+      ProviderScope(
+        child: MaterialApp(
+          theme: mornye ? MornyeTheme.build(Brightness.dark) : ThemeData(),
+          localizationsDelegates: AppLocalizations.localizationsDelegates,
+          supportedLocales: AppLocalizations.supportedLocales,
+          home: Scaffold(
+            body: Builder(
+              builder: (context) => TextButton(
+                onPressed: () async {
+                  try {
+                    selection = await showIosLibraryFolderSheet(context);
+                  } catch (error) {
+                    failure = error;
+                  }
+                },
+                child: const Text('Add folder'),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+    await tester.tap(find.text('Add folder'));
+    await tester.pumpAndSettle();
+  }
+
+  for (final mornye in [false, true]) {
+    testWidgets('internal music bypasses Files (Mornye=$mornye)', (
+      tester,
+    ) async {
+      final music = File('${documents.path}/SpotiFLAC/example.flac');
+      music.parent.createSync(recursive: true);
+      music.writeAsBytesSync([1, 2, 3]);
+      await openSheet(tester, mornye: mornye);
+      expect(find.text('Choose from Files'), findsOneWidget);
+      await tester.tap(find.text('App Documents Folder'));
+      await tester.pumpAndSettle();
+      expect(selection?.path, documents.path);
+      expect(selection?.bookmark, isEmpty);
+      expect(calls, isEmpty);
+      expect(music.readAsBytesSync(), [1, 2, 3]);
+      expect(failure, isNull);
+      expect(tester.takeException(), isNull);
+    });
+  }
+
+  testWidgets('external selection retains its native access bookmark', (
+    tester,
+  ) async {
+    await openSheet(tester);
+    await tester.tap(find.text('Choose from Files'));
+    await tester.pumpAndSettle();
+    expect(calls, ['pickIosDirectory']);
+    expect(selection?.path, '/external/Music');
+    expect(selection?.bookmark, 'granted-folder-bookmark');
+    expect(failure, isNull);
+  });
+
+  testWidgets('dismissing the choice does not select or create a folder', (
+    tester,
+  ) async {
+    await openSheet(tester);
+    await tester.tapAt(const Offset(10, 10));
+    await tester.pumpAndSettle();
+    expect(selection, isNull);
+    expect(calls, isEmpty);
+    expect(documents.existsSync(), isFalse);
+  });
+
+  testWidgets('cancelling Files leaves the library selection unchanged', (
+    tester,
+  ) async {
+    messenger.setMockMethodCallHandler(backend, (_) async => null);
+    await openSheet(tester);
+    await tester.tap(find.text('Choose from Files'));
+    await tester.pumpAndSettle();
+    expect(selection, isNull);
+    expect(failure, isNull);
+    expect(documents.existsSync(), isFalse);
+  });
+
+  testWidgets('Files errors return to the caller for a visible error', (
+    tester,
+  ) async {
+    messenger.setMockMethodCallHandler(backend, (_) async {
+      throw PlatformException(code: 'BOOKMARK_FAILED');
+    });
+    await openSheet(tester);
+    await tester.tap(find.text('Choose from Files'));
+    await tester.pumpAndSettle();
+    expect(selection, isNull);
+    expect(failure, isA<PlatformException>());
+    expect(documents.existsSync(), isFalse);
+  });
+}