How to get result of rootBundle.loadString(key) during flutter widget test?

Question

I want to read a file from an asset during widget build with help of rootBundle but when I tried to call rootBundle.loadString('assets/myJsonAsset.json') like below :

testWidgets('load assets', (WidgetTester tester) async {
      final result = await rootBundle.loadString('assets/myJsonAsset.json');
      //above loadString method never return any result
      expect(result, isA<String>());
    });

then it causes the error :

Unable to load asset: assets/myJsonAsset.json

And the rootBundle.loadString('assets/myJsonAsset.json') never return any result.

Answer 1

Try to add this line to be executed before your tests:

TestWidgetsFlutterBinding.ensureInitialized();

This function will make your assets available for tests