Icon class

main.dart

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.center,
      textBaseline: TextBaseline.alphabetic,
      children: [
        Icon(
          Icons.widgets,
          size: 50,
          color: Colors.blue,
        ),
        Icon(
          Icons.widgets,
          size: 50,
          color: Colors.red,
        ),
      ],
    );
  }
}

test.dart

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Directionality(
      textDirection: TextDirection.ltr,
      child: Container(
        color: Color(0xffeeeeee),
        child: Center(
          child: Container(
            child: MyWidget(),
            color: Color(0xffcccccc),
          ),
        ),
      ),
    );
  }
}

Future<void> main() async {
  final completer = Completer<void>();
  
  runApp(MyApp());

  WidgetsFlutterBinding.ensureInitialized()
      .addPostFrameCallback((timestamp) async {
    completer.complete();
  });
  
  await completer.future;

  final controller = LiveWidgetController(WidgetsBinding.instance);

  final rows = controller.widgetList(find.byType(Row));

  if (rows.length == 0) {
    _result(false, ['Couldn\'t find a Row!']);
    return;
  }

  if (rows.length > 1) {
    _result(false, ['Found ${rows.length} Rows, rather than just one.']);
    return;
  }

  final row = rows.first as Row;

  if (row.mainAxisSize != MainAxisSize.max) {
    _result(false, ['It\'s best to leave the mainAxisSize set to MainAxisSize.max, so there\'s space for the alignments to       take effect.']);
    return;
  }
  
    if (row.children.length != 3 || row.children.any((w) => w is! Icon)) {
    _result(false, ['Row should have three children, all Icon widgets.']);
    return;
  }

    final icon = row.children[2] as Icon;
  
  if (icon.color != Colors.amber) {
    _result(false, ['Add a third Icon. Give the Icon a size of 50 and a color of Colors.amber.']);
    return;
  }
  
  _result(true, ['The code displays three Icons in blue, red, and amber.']);
  
}