Create use case for get top headlines news

lib/feature/domain/usecase/gettopheadlinesnews/get_top_headlines_news.dart

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+import 'package:dartz/dartz.dart';
+import 'package:flutter_news_app/core/error/failure.dart';
+import 'package:flutter_news_app/core/usecase/usecase.dart';
+import 'package:flutter_news_app/feature/data/model/topheadlinesnews/top_headlines_news_response_model.dart';
+import 'package:flutter_news_app/feature/domain/repository/news/news_repository.dart';
+import 'package:meta/meta.dart';
+
+class GetTopHeadlinesNews implements UseCase<TopHeadlinesNewsResponseModel, NoParams> {
+ final NewsRepository newsRepository;
+
+ GetTopHeadlinesNews({@required this.newsRepository});
+
+ @override
+ Future<Either<Failure, TopHeadlinesNewsResponseModel>> call(NoParams params) async {
+ return await newsRepository.getTopHeadlinesNews();
+ }
+}

test/feature/domain/usecase/gettopheadlinesnews/get_top_headlines_news_test.dart

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+import 'dart:convert';
+
+import 'package:dartz/dartz.dart';
+import 'package:flutter_news_app/core/usecase/usecase.dart';
+import 'package:flutter_news_app/feature/data/model/topheadlinesnews/top_headlines_news_response_model.dart';
+import 'package:flutter_news_app/feature/domain/repository/news/news_repository.dart';
+import 'package:flutter_news_app/feature/domain/usecase/gettopheadlinesnews/get_top_headlines_news.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+
+import '../../../../fixture/fixture_reader.dart';
+
+class MockNewsRepository extends Mock implements NewsRepository {}
+
+void main() {
+ GetTopHeadlinesNews getTopHeadlinesNews;
+ MockNewsRepository mockNewsRepository;
+
+ setUp(() {
+ mockNewsRepository = MockNewsRepository();
+ getTopHeadlinesNews = GetTopHeadlinesNews(newsRepository: mockNewsRepository);
+ });
+
+ test(
+ 'make sure that NewsRepository successfully gets a successful or failed response from the getTopHeadlinesNews '
+ 'endpoint',
+ () async {
+ // arrange
+ final tTopHeadlinesNewsResponseModel = TopHeadlinesNewsResponseModel.fromJson(
+ json.decode(
+ fixture('top_headlines_news_response_model.json'),
+ ),
+ );
+ when(mockNewsRepository.getTopHeadlinesNews()).thenAnswer((_) async => Right(tTopHeadlinesNewsResponseModel));
+
+ // act
+ final result = await getTopHeadlinesNews(NoParams());
+
+ // assert
+ expect(result, Right(tTopHeadlinesNewsResponseModel));
+ verify(mockNewsRepository.getTopHeadlinesNews());
+ verifyNoMoreInteractions(mockNewsRepository);
+ },
+ );
+}