How to make a "WidgetTest" call the "onCameraMove" method?

Question

I would like the onCameraMove method to be called when moveCamera is called.

I tried to mock platform channel without success.

import 'dart:async';

import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  testWidgets('GoogleMaps onCameraMove', (WidgetTester tester) async {
    final Completer<GoogleMapController> controllerCompleter =
        Completer<GoogleMapController>();
    final cameraMoveCompleter = Completer<bool>();

    await tester.pumpWidget(Directionality(
      textDirection: TextDirection.ltr,
      child: GoogleMap(
        initialCameraPosition: const CameraPosition(target: LatLng(1, 2)),
        onMapCreated: (GoogleMapController c) {
          controllerCompleter.complete(c);
        },
        onCameraMove: (position) {
          cameraMoveCompleter.complete(true);
        },
      ),
    ));
    await tester.pumpAndSettle();

    final GoogleMapController controller = await controllerCompleter.future;
    await controller.moveCamera(CameraUpdate.newLatLng(const LatLng(2, 3)));

    await tester.pumpAndSettle();

    expect(cameraMoveCompleter.isCompleted, true);
  });
}

score 0 · Accepted Answer · answered Apr 25 '23 at 09:52

I find the right way for mock EventChannel.

import 'dart:async';

import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

void main() {
  TestWidgetsFlutterBinding.ensureInitialized();

  testWidgets('GoogleMaps onCameraMove', (WidgetTester tester) async {
    SystemChannels.platform_views
        .setMockMethodCallHandler((final MethodCall call) {
      switch (call.method) {
        case 'create':
          return Future<int>.sync(() => 1);
        default:
          return Future<void>.sync(() {});
      }
    });
    const channel = 'plugins.flutter.io/google_maps_0';
    const MethodChannel(channel).setMockMethodCallHandler(
      (final MethodCall call) async {
        if (call.method == 'camera#move') {
          final cameraPosition =
              CameraPosition.fromMap(call.arguments['cameraUpdate'][1])!;
          await TestDefaultBinaryMessengerBinding
              .instance?.defaultBinaryMessenger
              .handlePlatformMessage(
            channel,
            const StandardMethodCodec().encodeMethodCall(
              MethodCall(
                'camera#onMove',
                <dynamic, dynamic>{
                  'mapId': 0,
                  'position': cameraPosition.toMap(),
                },
              ),
            ),
            null,
          );
        }
      },
    );
    final controllerCompleter = Completer<GoogleMapController>();
    final cameraMoveCompleter = Completer<CameraPosition>();
    await tester.pumpWidget(Directionality(
      textDirection: TextDirection.ltr,
      child: GoogleMap(
        initialCameraPosition: const CameraPosition(target: LatLng(1, 2)),
        onMapCreated: (GoogleMapController c) {
          controllerCompleter.complete(c);
        },
        onCameraMove: (position) {
          cameraMoveCompleter.complete(position);
        },
      ),
    ));
    await tester.pumpAndSettle();
    final GoogleMapController controller = await controllerCompleter.future;
    const position = CameraPosition(target: LatLng(2, 3));
    await controller.moveCamera(CameraUpdate.newCameraPosition(position));
    await tester.pumpAndSettle();
    expect(cameraMoveCompleter.isCompleted, true);
    expect(await cameraMoveCompleter.future, position);
  });
}

How to make a "WidgetTest" call the "onCameraMove" method?

1 Answers1