Inject dependencies for upload and playlist tests

lib/features/track_upload/data/datasources/upload_track_remote_datasource.dart

@@ -22,9 +22,22 @@ import 'package:flutter/foundation.dart';
 /// - Does NOT return domain entities, only data models
 
 class UploadTrackRemoteDataSource {
+  UploadTrackRemoteDataSource({
+    Dio? dio,
+    Future<MultipartFile> Function(String path, DioMediaType contentType)?
+    multipartFileFactory,
+  }) : _dio = dio ?? apiClient.dio,
+       _multipartFileFactory =
+           multipartFileFactory ??
+           ((path, contentType) {
+             return MultipartFile.fromFile(path, contentType: contentType);
+           });
+
   // Uses the shared ApiClient your team leader built
   // Auth token is attached automatically — you don't touch it here
-  final Dio _dio = apiClient.dio;
+  final Dio _dio;
+  final Future<MultipartFile> Function(String path, DioMediaType contentType)
+  _multipartFileFactory;
 
   // ── Fetch Tags ─────────────────────────────────────────────────────────────
 
@@ -85,10 +98,10 @@ class UploadTrackRemoteDataSource {
         'genre': genre,
         'is_public': isPublic, // Pass as boolean
         'is_hidden': isHidden,
-        'audio_file': await MultipartFile.fromFile(
+        'audio_file': await _multipartFileFactory(
           // spec: 'audio_file'
           audioFile.path,
-          contentType: DioMediaType.parse(audioMime),
+          DioMediaType.parse(audioMime),
         ),
       };
 
@@ -103,10 +116,10 @@ class UploadTrackRemoteDataSource {
       // Cover image — spec: 'cover_image'
       if (artworkFile != null) {
         final artMime = lookupMimeType(artworkFile.path) ?? 'image/jpeg';
-        fields['cover_image'] = await MultipartFile.fromFile(
+        fields['cover_image'] = await _multipartFileFactory(
           // spec: 'cover_image'
           artworkFile.path,
-          contentType: DioMediaType.parse(artMime),
+          DioMediaType.parse(artMime),
         );
       }
 

lib/features/track_upload/domain/usecases/upload_track_usecase.dart

@@ -28,8 +28,16 @@ import 'package:rythmify/features/track_upload/domain/repositories/upload_track_
 
 class UploadTrackUseCase {
   final UploadTrackRepository repository;
+  final File Function(String path) fileFactory;
+  final bool Function(File file) fileExists;
 
-  const UploadTrackUseCase(this.repository);
+  const UploadTrackUseCase(
+    this.repository, {
+    this.fileFactory = File.new,
+    bool Function(File file)? fileExists,
+  }) : fileExists = fileExists ?? _defaultFileExists;
+
+  static bool _defaultFileExists(File file) => file.existsSync();
 
   Future<Either<Failure, String>> call({
     required TrackDraft draft,
@@ -47,7 +55,7 @@ class UploadTrackUseCase {
 
     // Double-check audio file still exists on device
     //commented for teting will uncomment later
-    if (!audioFile.existsSync()) {
+    if (!fileExists(audioFile)) {
       return const Left(
         FileFailure('Audio file no longer exists on your device.'),
       );

lib/features/track_upload/presentation/providers/upload_track_provider.dart

@@ -212,7 +212,8 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
 
   //added in backend integration phase
   Future<void> startUpload({
-    required WidgetRef ref,
+    WidgetRef? ref,
+    UploadTrackUseCase? useCaseOverride,
     required void Function(String trackId) onSuccess,
     required void Function(String error) onError,
   }) async {
@@ -224,8 +225,14 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
       draft.copyWith(status: UploadStatus.uploading, uploadProgress: 0.0),
     );
 
-    // Get the usecase
-    final useCase = ref.read(uploadUseCaseProvider);
+    // Get the usecase. Production passes WidgetRef; tests can inject the
+    // use case directly because WidgetRef is sealed.
+    final useCase = useCaseOverride ?? ref?.read(uploadUseCaseProvider);
+    if (useCase == null) {
+      _updateDraft(state.draft!.copyWith(status: UploadStatus.error));
+      onError('Upload service unavailable.');
+      return;
+    }
 
     // Call usecase with draft and progress callback
     final result = await useCase(
@@ -257,9 +264,14 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
   }
 
   //added in back integration to fix 400 error when ftetching genres
-  Future<void> fetchGenres(WidgetRef ref) async {
+  Future<void> fetchGenres([
+    WidgetRef? ref,
+    UploadTrackRemoteDataSource? dataSourceOverride,
+  ]) async {
     try {
-      final dataSource = ref.read(_uploadDataSourceProvider);
+      final dataSource =
+          dataSourceOverride ?? ref?.read(_uploadDataSourceProvider);
+      if (dataSource == null) return;
       final genres = await dataSource.fetchGenres();
       state = state.copyWith(availableGenres: genres);
       debugPrint('Genres loaded: $genres');
@@ -268,9 +280,14 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
     }
   }
 
-  Future<void> fetchTags(WidgetRef ref) async {
+  Future<void> fetchTags([
+    WidgetRef? ref,
+    UploadTrackRemoteDataSource? dataSourceOverride,
+  ]) async {
     try {
-      final dataSource = ref.read(_uploadDataSourceProvider);
+      final dataSource =
+          dataSourceOverride ?? ref?.read(_uploadDataSourceProvider);
+      if (dataSource == null) return;
       final tags = await dataSource.fetchTags();
       state = state.copyWith(availableTags: tags);
       debugPrint('Tags loaded: $tags');
@@ -305,7 +322,9 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
   }
 
   Future<void> handleUpdate({
-    required WidgetRef ref,
+    WidgetRef? ref,
+    Future<void> Function(String trackId, Map<String, dynamic> data)?
+    updateOverride,
     required void Function() onSuccess,
     required void Function(String error) onError,
   }) async {
@@ -314,7 +333,20 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
 
     state = state.copyWith(isLoading: true);
 
-    final updateTrack = ref.read(updateTrackUseCaseProvider);
+    final updateTrack =
+        updateOverride ??
+        (ref == null
+            ? null
+            : (String trackId, Map<String, dynamic> data) =>
+                  ref.read(updateTrackUseCaseProvider).call(trackId, data));
+    if (updateTrack == null) {
+      state = state.copyWith(
+        isLoading: false,
+        errorMessage: 'Update service unavailable.',
+      );
+      onError('Update service unavailable.');
+      return;
+    }
 
     final Map<String, dynamic> data = {
       "title": draft.title,
@@ -330,7 +362,7 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
     };
 
     try {
-      await updateTrack.call(draft.trackId!, data);
+      await updateTrack(draft.trackId!, data);
       state = state.copyWith(isLoading: false);
       onSuccess();
     } catch (e) {
@@ -340,7 +372,8 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
   }
 
   Future<void> handleDelete({
-    required WidgetRef ref,
+    WidgetRef? ref,
+    Future<void> Function(String trackId)? deleteOverride,
     required void Function() onSuccess,
     required void Function(String error) onError,
   }) async {
@@ -349,10 +382,23 @@ class UploadFormNotifier extends Notifier<UploadFormState> {
 
     state = state.copyWith(isLoading: true);
 
-    final deleteTrack = ref.read(deleteTrackUseCaseProvider);
+    final deleteTrack =
+        deleteOverride ??
+        (ref == null
+            ? null
+            : (String trackId) =>
+                  ref.read(deleteTrackUseCaseProvider).call(trackId));
+    if (deleteTrack == null) {
+      state = state.copyWith(
+        isLoading: false,
+        errorMessage: 'Delete service unavailable.',
+      );
+      onError('Delete service unavailable.');
+      return;
+    }
 
     try {
-      await deleteTrack.call(draft.trackId!);
+      await deleteTrack(draft.trackId!);
       state = state.copyWith(isLoading: false);
       onSuccess();
     } catch (e) {