如何在视图模型中测试提供者

Question

I have a view model that a view uses, i want to write a unit test for one of the functions which contains a provider. The function is something like this

Future<String> onSubmit(BuildContext context) async {

PersonProvider personProvider = Provider.of<PersonProvider>(context,listen: false);

String userId = personProvider.user.id;
isLoading = true;
return 'hello';

});}

Is there anyway I can test this, or I have to refactor code

Answer 1

You should refactor your code, if that function is in a ViewModel the problem is that it should not know nothing or as little as possible of the presentation layer. So it should NOT depend on the BuildContext , instead pass in the needed dependencies either directly to the function:

Future<String> onSubmit(PersonProvider personProvider) async {


String userId = personProvider.user.id;
isLoading = true;
return 'hello';

});}

Or inject it to the ViewModel constructor, that way you decouple your viewModel from the UI, and from PersonProvider , which can now be passed as a mock for testing.

If what you are referring to as viewmodel is really just a presenter you could do widget tests and providr a Mock PersonProvider implementation to the widget tree.