.Net Core 单元测试获取配置文件节点值

单元测试类：

ServiceProvider _serviceProvider;
        IConfiguration _config;

        [SetUp]
        public void Setup()
        {
            _config = new ConfigurationBuilder()
            .Add(new JsonConfigurationSource { Path = "appsettings.json", ReloadOnChange = true })
            .Build();

            IServiceCollection services = new ServiceCollection();

            _serviceProvider = services.BuildServiceProvider();

        }

        [Test]
        public void IQueryRecordService_UnitTest()
        {
            var config = _config.Get();
            var demoModelCodes = config.DemoModelCodes;

            var list = new List