我正在尝试在 AppService 的 Xunit 测试中实现依赖注入(inject)。理想的目标是运行原始应用程序 Startup/configuration，并使用 Startup 中的任何依赖注入(inject)，而不是在我的测试中再次重新初始化所有 DI，这就是整个目标。

更新:Mohsen 的回答很接近。需要更新几个语法/需求错误才能工作。

由于某种原因，原始应用程序可以运行并且可以调用部门应用程序服务。但是，它不能调用 Xunit。最后使用原始应用程序的启动和配置让 Testserver 工作。 现在收到以下错误:

Message: The following constructor parameters did not have matching fixture data: IDepartmentAppService departmentAppService

namespace Testing.IntegrationTests
{
    public class DepartmentAppServiceTest
    {
        public DBContext context;
        public IDepartmentAppService departmentAppService;

        public DepartmentAppServiceTest(IDepartmentAppService departmentAppService)
        {
            this.departmentAppService = departmentAppService;
        }

        [Fact]
        public async Task Get_DepartmentById_Are_Equal()
        {
            var options = new DbContextOptionsBuilder<SharedServicesContext>()
                .UseInMemoryDatabase(databaseName: "TestDatabase")
                .Options;
            context = new DBContext(options);

            TestServer _server = new TestServer(new WebHostBuilder()
                .UseContentRoot("C:\\OriginalApplication")
                .UseEnvironment("Development")
                .UseConfiguration(new ConfigurationBuilder()
                    .SetBasePath("C:\\OriginalApplication")
                    .AddJsonFile("appsettings.json")
                    .Build()).UseStartup<Startup>());

            context.Department.Add(new Department { DepartmentId = 2, DepartmentCode = "123", DepartmentName = "ABC" });
            context.SaveChanges();

            var departmentDto = await departmentAppService.GetDepartmentById(2);

            Assert.Equal("123", departmentDto.DepartmentCode);
        }
    }
}

我收到这个错误:

Message: The following constructor parameters did not have matching fixture data: IDepartmentAppService departmentAppService

需要像实际应用一样在测试中使用依赖注入(inject)。 原始应用程序执行此操作。以下答案目前还不够，一个使用不是当前目标的模拟，另一个答案使用 Controller 绕过问题目的。

注意:IDepartmentAppService 依赖 IDepartmentRepository，它也被注入(inject) Startup 类，以及 Automapper 依赖。这就是调用整个启动类的原因。

好的资源:

how to unit test asp.net core application with constructor dependency injection

Dependency injection in Xunit project

最佳答案

您将单元测试与集成测试混合在一起。 TestServer 用于集成测试，如果您想重用 Startup 类以避免再次注册依赖项，您应该使用 HttpClient 并对 Controller 进行 HTTP 调用和使用 IDepartmentAppService 的操作。

如果要进行单元测试，则需要设置 DI 并注册所有需要的依赖项以测试 IDepartmentAppService。

通过测试夹具使用 DI:

public class DependencySetupFixture
{
    public DependencySetupFixture()
    {
         var serviceCollection = new ServiceCollection();
         serviceCollection.AddDbContext<SharedServicesContext>(options => options.UseInMemoryDatabase(databaseName: "TestDatabase"));
         serviceCollection.AddTransient<IDepartmentRepository, DepartmentRepository>();
         serviceCollection.AddTransient<IDepartmentAppService, DepartmentAppService>();

         ServiceProvider = serviceCollection.BuildServiceProvider();
    }

    public ServiceProvider ServiceProvider { get; private set; }
}

public class DepartmentAppServiceTest : IClassFixture<DependencySetupFixture>
{
    private ServiceProvider _serviceProvide;

    public DepartmentAppServiceTest(DependencySetupFixture fixture)
    {
        _serviceProvide = fixture.ServiceProvider;
    }

    [Fact]
    public async Task Get_DepartmentById_Are_Equal()
    {
        using(var scope = _serviceProvider.CreateScope())
        {   
            // Arrange
            var context = scope.ServiceProvider.GetServices<SharedServicesContext>();
            context.Department.Add(new Department { DepartmentId = 2, DepartmentCode = "123", DepartmentName = "ABC" });
            context.SaveChanges();

            var departmentAppService = scope.ServiceProvider.GetServices<IDepartmentAppService>();

            // Act
            var departmentDto = await departmentAppService.GetDepartmentById(2);

            // Arrange
            Assert.Equal("123", departmentDto.DepartmentCode);           
        }
    }
}

在单元测试中使用依赖注入(inject)不是一个好主意，你应该避免这种情况。顺便说一下，如果您不想重复注册依赖项，您可以将 DI 配置包装在另一个类中，然后在任何您想要的地方使用该类。

通过 Startup.cs 使用 DI:

public class IocConfig
{
    public static IServiceCollection Configure(IServiceCollection services, IConfiguration configuration)
    {
         serviceCollection
            .AddDbContext<SomeContext>(options => options.UseSqlServer(configuration["ConnectionString"]));
         serviceCollection.AddScoped<IDepartmentRepository, DepartmentRepository>();
         serviceCollection.AddScoped<IDepartmentAppService, DepartmentAppService>();
         .
         .
         .

         return services;
    }
}

在Startup 类和ConfigureServices 方法中只使用IocConfig 类:

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
         IocConfig.Configure(services, configuration);

         services.AddMvc();
         .
         .
         .

如果您不想使用IocConfig 类，请更改Startup 类中的ConfigureServices:

public IServiceCollection ConfigureServices(IServiceCollection services)
{
     .
     .
     .
     return services;

并在测试项目中重用IocConfig或Startup类:

public class DependencySetupFixture
{
    public DependencySetupFixture()
    {
          var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json", false, true));
         configuration = builder.Build();

         var services = new ServiceCollection();

         // services = IocConfig.Configure(services, configuration)
         // or
         // services = new Startup(configuration).ConfigureServices(services);

         ServiceProvider = services.BuildServiceProvider();
    }

    public ServiceProvider ServiceProvider { get; private set; }
}

在测试方法中:

[Fact]
public async Task Get_DepartmentById_Are_Equal()
{
    using (var scope = _serviceProvider.CreateScope())
    {
        // Arrange
        var departmentAppService = scope.ServiceProvider.GetServices<IDepartmentAppService>();

        // Act
        var departmentDto = await departmentAppService.GetDepartmentById(2);

        // Arrange
        Assert.Equal("123", departmentDto.DepartmentCode);
    }
}

关于c# - Net Core : Execute All Dependency Injection in Xunit Test for AppService, 存储库等，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57331395/