Test

test.dart

  testWidgets('Ellipsis is passed to the inner TextPainter when provided', (WidgetTester tester) async {
    await tester.pumpWidget(
      const MaterialApp(
        home: Material(
          child: SelectableText(
            'overflow',
            maxLines: 1,
            style: TextStyle(overflow: TextOverflow.ellipsis),
          ),
        ),
      ),
      Duration.zero,
      EnginePhase.build
    );

    final EditableTextState editableTextState = tester.state(find.byType(EditableText));
    //expect(editableTextState.renderEditable.textPainter.ellipsis, kDefaultEllipsis);
    
    // Getting no element
    //final SelectableTextState state = tester.state<SelectableTextState>(find.byElementType(SelectableTextState));
    final box = editableTextState.context.findRenderObject() as RenderBox?;
    expect(box?.size.width, 8);