test(mobile): add unit tests for view intent pending/flush flow

mobile/test/services/view_intent_service_test.dart

@@ -0,0 +1,90 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:immich_mobile/models/view_intent/view_intent_attachment.model.dart';
+import 'package:immich_mobile/repositories/view_handler.repository.dart';
+import 'package:immich_mobile/services/view_intent_service.dart';
+import 'package:mocktail/mocktail.dart';
+
+class MockViewHandlerRepository extends Mock implements ViewHandlerRepository {}
+
+void main() {
+  late MockViewHandlerRepository repository;
+  late ViewIntentService service;
+
+  const attachment = ViewIntentAttachment(
+    path: '/tmp/file.jpg',
+    type: ViewIntentAttachmentType.image,
+    localAssetId: '42',
+  );
+
+  setUp(() {
+    repository = MockViewHandlerRepository();
+    service = ViewIntentService(repository);
+  });
+
+  test('checkViewIntent does nothing when no attachment', () async {
+    when(() => repository.checkViewIntent()).thenAnswer((_) async => null);
+
+    var called = 0;
+    service.onViewMedia = (_) async {
+      called++;
+    };
+
+    await service.checkViewIntent();
+
+    expect(called, 0);
+    verify(() => repository.checkViewIntent()).called(1);
+  });
+
+  test('checkViewIntent calls handler immediately when handler is set', () async {
+    when(() => repository.checkViewIntent()).thenAnswer((_) async => attachment);
+
+    List<ViewIntentAttachment>? received;
+    service.onViewMedia = (attachments) async {
+      received = attachments;
+    };
+
+    await service.checkViewIntent();
+
+    expect(received, isNotNull);
+    expect(received, hasLength(1));
+    expect(received!.first, attachment);
+    verify(() => repository.checkViewIntent()).called(1);
+  });
+
+  test('checkViewIntent stores pending attachment when handler is not set', () async {
+    when(() => repository.checkViewIntent()).thenAnswer((_) async => attachment);
+
+    await service.checkViewIntent();
+
+    List<ViewIntentAttachment>? received;
+    service.onViewMedia = (attachments) async {
+      received = attachments;
+    };
+    await service.flushPending();
+
+    expect(received, isNotNull);
+    expect(received, hasLength(1));
+    expect(received!.first, attachment);
+  });
+
+  test('defer + flushPending does nothing without handler, then flushes once when handler appears', () async {
+    service.defer(attachment);
+
+    // No handler yet: should keep pending.
+    await service.flushPending();
+
+    var called = 0;
+    List<ViewIntentAttachment>? received;
+    service.onViewMedia = (attachments) async {
+      called++;
+      received = attachments;
+    };
+
+    await service.flushPending();
+    await service.flushPending();
+
+    expect(called, 1);
+    expect(received, hasLength(1));
+    expect(received!.first, attachment);
+  });
+}