In this Unit Testing with Flutter tutorial, you’ll improve your programming skills by learning how to add unit tests to your apps.
Thanks lowery for writing this tutorial. can you write another advanced Testing tutorial?
Hi Hashem!
Thank you for writing in and expressed your interest to learn more about Flutter Testing. I am almost done with Flutter Widget Testing which should be released in a few weeks time!
If you have specific topics of interests to you, please list it down so that I can try to accommodate them in my next tutorial 
Cheers
Looking forward to the new tutorial as well.
Looking forward to hear all your feedbacks after publishing it as well
Hello @lawrey, I am hoping I can get some guidance on what /i might be doing wrong when I try to test a widget in my App.
I am just getting started with unit testing in Flutter, and I have hit a bit of a wall. I have a fairly simple app located here:
https://github.com/chuckntaylor/kwjs_flutter_demo
The app is essentially a list view of events where you can tap on one to read more details about the event.
I have two screens for this: events_screen.dart for the list view, and event_screen.dart for the details. I have been trying to write my tests in events_screen_test.dart
My testing difficulties are with the events screen (the list view). After running await tester.pumpWidget(MaterialApp(home: EventsScreen()) I can use find.text('Events') for example to find the title in the AppBar, but I cannot find any of the elements that make up the list.
To clarify further. I am using get_it as a serviceLocator to get the viewModel for the EventsScreen when it loads. The viewModel is the ChangeNotifierProvider, and EventsScreen contains a Consumer to update the list. in EventsScreen initState(), it calls loadEvents() on the viewModel. After loadEvents() is done, the viewModel calls notifyListeners(), so that EventsScreen can update.
How do I ensure that all these steps occur so that I can properly test if the EventsScreen is rendering properly?
I could be approaching this all wrong, so any advice is appreciated.
I have solved my problem, but perhaps someone can shed some light on this. In the end I executed:
await tester.pumpWidget(MaterialApp(home: EventsScreen(),));
// followed immediately by this second pump without arguments
await tester.pump();
At this point, the Widget tree was complete and I could create Finders as I hoped and could run all my expect statements without issue.
I am not sure exactly why this works though.
Hey @chuck_taylor, sorry for the late response. If I understand your issue correctly, you were facing issues finding elements to interact within your test suite.
What you did is the right approach, pumpWidget calls runApp, and also trigger a frame to paint the app. This is sufficient if your UI and data are all provided immediately from the app, or I could call them static data. (i.e., labels and texts)
When you have a structure (i.e. list, collections) with repeated data models, pump becomes essential to trigger a rebuild since the data-loading process will happen post-runApp.
@lawrey Thank you for taking the time to reply. That certainly clarifies why I didn’t have the data from the viewModel until I ran the pump method a second time. Looking forward to your next article!
This tutorial is more than six months old so questions are no longer supported at the moment for it. Thank you!