I'm having trouble with testing part while making flutter package - flutter

Question

I want to develop a more advanced version of the ListView widget as a package. This is my first package.
I wrote a code like this:
modern_card_listview.dart:
library modern_card_listview;
import 'package:flutter/material.dart';
class CardListView extends StatefulWidget {
List items;
CardListView({Key? key, required this.items}) : super(key: key);
#override
State<CardListView> createState() => _CardListViewState();
}
class _CardListViewState extends State<CardListView> {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: ListView.builder(
itemCount: widget.items.length,
itemBuilder: ((context, index) {
return Card(
child: ListTile(
title: widget.items[index],
),
);
}),
),
),
);
}
}
I guess I need to use the dart file in the test folder to test the code.
modern_card_listview_test.dart:
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:modern_card_listview/modern_card_listview.dart';
CardListView _listView = CardListView(
items: const ["Bu bir", "Bu iki", "Bu uc", "Bu dort", "Bu bes"]);
void main() {
runApp(const App());
}
class App extends StatelessWidget {
const App({super.key});
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: _listView,
),
);
}
}
How can I try the package I wrote? When I ran the code above, No tests were found. I get an error.This is my first pack and I'm still new. I would be grateful if you help.
I couldn't find a solution