How to test Flutter widgets on different screen sizes?

Question

I have a Flutter widget which shows extra data depending on the screen size. Does anyone know a way of testing this widget on multiple different screen sizes?

I've had a look through the widget_tester source code but can't find anything.

Answer 1

You can specify custom surface size by using WidgetTester

The following code will run a test with a screen size of 42x42

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

void main() {
  testWidgets("foo", (tester) async {
    tester.binding.window.physicalSizeTestValue = Size(42, 42);

    // resets the screen to its orinal size after the test end
    addTearDown(tester.binding.window.clearPhysicalSizeTestValue);

    // TODO: do something
  });
}