Flutter 颤振：无法使用rootBundle读取本地json文件

代码：

错误：

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

void main() {

String abiStringFile="";
String path = "assets/data.json";
setUp(() async {

abiStringFile = await rootBundle.loadString(path);

});

test("Run Please", (){
print(abiStringFile);
});
}

pubspec.yaml文件

Null check operator used on a null value.
Problem in PlatfromAssetBundle.load from services/asset_bundle.dart:223

---

尝试在

SetUp（）

的开头写下以下内容：

flutter:

   uses-material-design: true

   assets:
     - assets/data.json

TestWidgetsFlutterBinding.ensureInitialized();