Unit testing 值不能为null。（参数和连接字符串和）Xunit测试

我正试图用Xunit编写单元测试：

  public class UserTest
{

    private readonly TestServer _server;
    private readonly HttpClient _client;

    public UserTest()
    {
        _server = new TestServer(new WebHostBuilder().UseStartup<Startup>());
        _client = _server.CreateClient();
    }

    [Fact]
    public async Task GetAllUserTest()
    {
        var request = new HttpRequestMessage(new HttpMethod("Get"), "/Api/Users");

        var response =await _client.SendAsync(request);

        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
    }
}

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我假设您的单元测试与API位于不同的项目中？单元测试项目运行在与API不同的目录中，因此它们无法“看到”API可以看到的

appsettings.json

文件，导致您看到此错误

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但是，您确实不希望单元测试发出真正的HTTP请求。解决这个问题的方法是使用

HttpClient

在你的链接中，这是一篇关于模仿

HttpClient

的有用博文，代码var subjectiondertest=newmytestclass（HttpClient）；MyTestClass是什么意思？

 services.AddDbContext<BlogProjectContext>(option =>
        option.UseSqlServer(Configuration.GetConnectionString("BlogProjectConnection"))
        );

    {
  "AppSettings": {
    "Secret": "This is the secret key and its very important"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "BlogProjectConnection": "Data Source=.;Initial Catalog=BlogProject_DB;Integrated Security=True"

  }
}