How to mock http request in flutter integration test? - dart

Question

I'm trying to do so using Mockito, this is my test:
import 'package:http/http.dart' as http;
import 'package:utgard/globals.dart' as globals;
import 'package:flutter_driver/flutter_driver.dart';
import 'package:test/test.dart';
import 'package:mockito/mockito.dart';
class MockClient extends Mock implements http.Client {}
void main() {
group('Login flow', () {
final SerializableFinder loginContinuePasswordButton =
find.byValueKey('login_continue_password_button');
FlutterDriver driver;
setUpAll(() async {
driver = await FlutterDriver.connect();
});
tearDownAll(() async {
if (driver != null) {
//await driver.close();
}
});
test('login with correct password', () async {
final client = MockClient();
when(client.post('http://wwww.google.com'))
.thenAnswer((_) async => http.Response('{"title": "Test"}', 200));
globals.httpClient = client;
await driver.enterText('000000');
await driver.tap(loginContinuePasswordButton);
});
});
}
And this is my http request code:
Future<Map<String, dynamic>> post({
RequestType requestType,
Map<String, dynamic> body,
}) async {
final http.Response response =
await globals.httpClient.post('http://wwww.google.com');
print(response);
final Map<String, dynamic> finalResponse = buildResponse(response);
_managerErrors(finalResponse);
return finalResponse;
}
And here I have the global:
library utgard.globals;
import 'package:http/http.dart' as http;
http.Client httpClient = http.Client();
However I continue to receive http errors, that indicates to me that the http wasn't replaced by the mock.

Answer 1

The solution I found was to define the mock in test_driver/app.dart and call the runApp function after that:
import 'package:flutter/widgets.dart';
import 'package:flutter_driver/driver_extension.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:utgard/business/config/globals.dart';
import 'package:utgard/main.dart' as app;
class MockClient extends Mock implements http.Client {}
void main() {
enableFlutterDriverExtension();
final MockClient client = MockClient();
// make your mocks here
httpClient = client;
runApp(app.MyApp());
}

Answer 2

Instead of
when(client.post('http://wwww.google.com'))
.thenAnswer((_) async => http.Response('{"title": "Test"}', 200));
try any and then assert it later
when(
mockHttpClient.send(any),
).thenAnswer((_) async => http.Response('{"title": "Test"}', 200));
// ...
final String capt = verify(client.send(captureAny)).captured;
expect(capt, 'http://wwww.google.com');
There's a small chance the call param is not exactly what you mock, so go with any is safer.

Answer 3

We don't see the code you're testing, but it's unlikely that it is going to make this request :
client.post('http://wwww.google.com')
It is anyway a good practice to use mock json files, and you don't want to change the request anytime those mock files change.
I recommend you to use Mocktail instead of Mockito.
That way, you can simulate any call with any :
// Simulate any GET :
mockHttpClient.get(any()))
// Simulate any POST :
mockHttpClient.post(any()))
Here's the complete solution :
class MockClient extends Mock implements http.Client {}
class FakeUri extends Fake implements Uri {}
void main() {
setUp(() {
registerFallbackValue(FakeUri()); // Required by Mocktail
});
tearDown(() {});
MockHttpClient mockHttpClient = MockHttpClient();
group('Login flow', () {
test('login with correct password', () async {
when(() => mockHttpClient.get(any())).thenAnswer(((_) async {
return Response(mockWeatherResponse, 200);
}));
// Call the functions you need to test here
}
}
}