Cannot find Widgets in test inside of Consumer Widget of Provider

Issue

I created the following Flutter test for my widget

testWidgets("", (WidgetTester tester) async {
      await tester.pumpWidget(
        ChangeNotifierProvider<SettingsViewProvider>(
          create: (context) => SettingsViewProvider(),
          child: MaterialApp(
            localizationsDelegates: [S.delegate],
            home: SettingsScreen(),
          ),
        ),
      );

      final textFormFieldFinder = find.byElementType(TextFormField);
      await tester.pump();
      expect(textFormFieldFinder, findsNWidgets(3));
    });

The widget is a stateful widget which uses a ChangeNotifierProvider and the Consumer surrounds a List of three “TextFormFields”.

Consumer<State>(
   builder: (context, value, child)=> Column(
       children: [TextFormField(...), TextFormField(...), TextFormField(...)];
   )
)

Expected: exactly 3 matching nodes in the widget tree

Actual: _ElementTypeFinder:

Which: means none were found but some were expected

Unfortunatly I receive that no widget is found in the widget tree.

Solution

As pointed out before, you should be using find.byType which is aimed at seaching Widgets rather than find.byElementType which deals with Elements.

Flutter has 3 UI building blocks:

Widgets (immutable) -> Elements (mutable) -> Render Objects
— they are not inherited from one another, those are separate types of objects with different purposes.

TextFormField is a Widget, while it is being passed to find.byElementType which expects an ancestor of Element

Answered By – Maxim Saplin

Answer Checked By – Katrina (FlutterFixes Volunteer)