Xunit 测试用例给出了涉及构造函数的错误答案

【问题标题】：Xunit Test case is giving an error involving the constructorXunit 测试用例给出了涉及构造函数的错误
【发布时间】：2020-10-23 13:21:19
【问题描述】：

我有一个接口定义为：

    public interface IProfessorsDAL
    {
        Task<(bool, string)> UploadToBlob(string filename, byte[] imageBuffer = null, Stream stream = null);
    }

我已经将类定义为：



public class ProfessorsMockDAL : IProfessorsDAL
    {
        private readonly IConfiguration _configuration;

        public ProfessorsMockDAL(IConfiguration configuration)
        {
            _configuration = configuration;
        }
 public static string stConnectionString { get; } = "AppSetting:StaConnectionString";

        public async Task<(bool, string)> UploadToBlob(string filename, byte[] imageBuffer = null, Stream stream = null)
        {
            CloudStorageAccount storageAccount = null;
            CloudBlobContainer cloudBlobContainer = null;
            string storageConnectionString = _configuration[stConnectionString];

            // Check whether the connection string can be parsed.
            if (CloudStorageAccount.TryParse(storageConnectionString, out storageAccount))
            {
                try
                {
                    // Create the CloudBlobClient that represents the Blob storage endpoint for the storage account.
                    CloudBlobClient cloudBlobClient = storageAccount.CreateCloudBlobClient();

                    // Create a container called 'uploadblob' and append a GUID value to it to make the name unique. 
                    cloudBlobContainer = cloudBlobClient.GetContainerReference("uploadblob");

                    // Get a reference to the blob address, then upload the file to the blob.
                    CloudBlockBlob cloudBlockBlob = cloudBlobContainer.GetBlockBlobReference(filename);


                    if (imageBuffer != null)
                    {
                        // OPTION A: use imageBuffer (converted from memory stream)
                        await cloudBlockBlob.UploadFromByteArrayAsync(imageBuffer, 0, imageBuffer.Length);
                    }
                    else if (stream != null)
                    {
                        // OPTION B: pass in memory stream directly
                        await cloudBlockBlob.UploadFromStreamAsync(stream);

                    }
                    else
                    {
                        return (false, null);
                    }

                    return (true, cloudBlockBlob.SnapshotQualifiedStorageUri.PrimaryUri.ToString());
                }
                catch (StorageException ex)
                {
                    return (false, null);
                }

            }
            else
            {
                return (false, null);
            }
        }

我正在尝试为相同的内容编写一个 Xunit 测试用例：

 public class UnitTest1
    {

        private readonly IProfessorsDAL _professorsDAL;

        public UnitTest1(IProfessorsDAL professorsDAL)
        {
            _professorsDAL = professorsDAL;
        }

        [Fact]
        public async Task UploadToBlob()
        {
    
            var fileMock = new Mock<IFormFile>();
            //Setup mock file using a memory stream
            var content = "Hello World from a Fake File";
            var fileName = "test.pdf";
            var ms = new MemoryStream();
            var writer = new StreamWriter(ms);
            writer.Write(content);
            writer.Flush();
            ms.Position = 0;
            fileMock.Setup(_ => _.OpenReadStream()).Returns(ms);
            fileMock.Setup(_ => _.FileName).Returns(fileName);
            fileMock.Setup(_ => _.Length).Returns(ms.Length);

            var file = fileMock.Object;


            var uploadSuccess = false;
            string uploadedUri = null;
            using (var stream = file.OpenReadStream())
            {
                (uploadSuccess, uploadedUri) = await _professorsDAL.UploadToBlob(file.FileName, null, stream);
            }


            Assert.True(uploadSuccess);

        }
    }

但是我在执行测试用例时遇到了这样的错误：

以下构造函数参数没有匹配的夹具数据：IProfessorsDALprofessorsDAL

我发现我需要模拟一些东西，但我不确定如何。任何人都可以就如何正确地做到这一点提出一些想法吗？此外，这个逻辑是正确的，因为我可以使用控制器中的端点正确上传文件。我的 appsettings.json 中有连接字符串

【问题讨论】：

您正在将一个接口注入到您的单元测试中。我从来没有见过——我很确定你不想那样做。您的单元测试应该实例化您要测试的类。
所以如果我尝试像var service = new ProfessorsDAL();这样实例化类，我需要在里面传递配置对象，我该怎么做？
你会创建一个模拟它。我真的很喜欢Moq 框架
我使用 Moq 框架来创建这个：var configuration = new Mock<IConfiguration>(); 并尝试使用与实例化参数相同的参数，但它显示：cannot convert from 'Moq.Mock<Microsoft.Extensions.Configuration.IConfiguration>' to 'Microsoft.Extensions.Configuration.IConfiguration'。很抱歉我是新手
var service = new ProfessorsDAL(configuration.Object)

标签： c# .net-core xunit

【解决方案1】：

我能够使用这段代码解决我的问题，而不是向单元测试注入接口：

var config = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();
var service = new ProfessorsMockDAL(config);

我刚刚使用在测试项目位置中使用 appsettings.json 构建的配置实例化了该类。

【讨论】：