如何在Flutter的小部件测试中执行缩放(按压缩放)多指手势？

import 'package:flutter/gestures.dart';
import 'package:flutter_test/flutter_test.dart';

testWidgets('测试缩放手势', (WidgetTester tester) async {
  await tester.pumpWidget(MyApp());

  // 获取要测试的小部件
  final widget = tester.widget<MyWidget>(find.byType(MyWidget));

  // 创建一个缩放手势
  final scaleGesture = await tester.createGesture();
  await scaleGesture.addPointer(location: Offset(100, 100));
  await scaleGesture.addPointer(location: Offset(200, 200));

  // 执行缩放手势
  await scaleGesture.scaleBy(0.5, Offset(150, 150));

  // 释放手势
  await scaleGesture.up();

  // 断言缩放后的结果
  expect(widget.scale, 0.5);
});