Flutter/Mockito. Testing API provider with mockito, problem with api headers - dart

Question

I want to test my provider with mockito plugin but there is a problem with, as i understand with headers.
shows null when i do print(response)
if i remove headers from API
headers: {
'X-Requested-With': 'XMLHttpRequest',
'Authorization': 'Bearer $token',
},
the test works fine but with headers:
NoSuchMethodError: The getter 'statusCode' was called on null.
Receiver: null
Tried calling: statusCode
dart:core Object.noSuchMethod
package:mba/resources/providers/post_provider.dart 38:20 PostProvider.fetchPosts
===== asynchronous gap ===========================
dart:async _AsyncAwaitCompleter.completeError
package:mba/resources/providers/post_provider.dart PostProvider.fetchPosts
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:mba/resources/providers/post_provider.dart PostProvider.fetchPosts
test/resources/providers/post_provider_test.dart 46:39 main.<fn>.<fn>
provider:
import 'package:http/http.dart' as http;
import 'package:mba/env.dart';
import 'package:mba/core/models/post_model.dart';
class PostProvider {
final http.Client client;
final String _api = API;
// Map<String, List<Post>> _postsList = Map();
PostProvider(this.client);
Future<Map<String, List<Post>>> fetchPosts(String token) async {
final response = await client.get(
'${_api}posts',
headers: {
'X-Requested-With': 'XMLHttpRequest',
'Authorization': 'Bearer $token',
},
);
print('-------------');
print(response);
print(response.statusCode);
print(response.body);
//todo: decode and mapping
if (response.statusCode == 200) {
return Map();
} else {
throw 'xxxx';
}
}
test file:
import 'dart:io';
import 'package:mba/resources/providers/post_provider.dart';
import 'package:mockito/mockito.dart';
import 'package:http/http.dart' as http;
import 'package:flutter_test/flutter_test.dart';
import 'package:matcher/matcher.dart';
class MockClient extends Mock implements http.Client {}
void main() {
String fixture(String name) =>
File('test/fixtures/posts/$name.json').readAsStringSync();
MockClient mockClient;
PostProvider dataSource;
setUp(() {
mockClient = MockClient();
dataSource = PostProvider(mockClient);
});
group('searchVideos', () {
test(
'returns YoutubeSearchResult when the call completes successfully',
() async {
when(
mockClient.get(
argThat(
startsWith('http://localhost:55005/api'),
),
),
).thenAnswer(
(_) async => http.Response(
fixture('posts'),
200,
headers: {'content-type': 'application/json; charset=utf-8'},
),
);
var result = await dataSource.fetchPosts('resocoder');
print(result);
},
);
});
}

Answer 1

Mockito will respond to your when sentence if and only if all args of the mockClient.get() matches what you have specified.
In you case, you specified an URL, and nothing more. As your code use an URL and headers mockito won't match and won't do your thenAnswer.
In your when sentence, you have to specify the headers argument to match you tested code
when(
mockClient.get(
argThat(
startsWith('http://localhost:55005/api'),
),
headers: anyNamed('headers'), // Add this line
),
).thenAnswer(...);
Here, the anyNamed('headers') will match any header.