最小起订量 IServiceProvider / IServiceScope

Question

我正在尝试为 IServiceProvider 创建一个 Mock（使用 Moq），以便我可以测试我的存储库 class:

public class ApiResourceRepository : IApiResourceRepository
{
    private readonly IServiceProvider _serviceProvider;

    public ApiResourceRepository(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
        _dbSettings = dbSettings;
    }

    public async Task<ApiResource> Get(int id)
    {
        ApiResource result;

        using (var serviceScope = _serviceProvider.
            GetRequiredService<IServiceScopeFactory>().CreateScope())
        {
            var context = serviceScope.ServiceProvider.GetRequiredService<ConfigurationDbContext>();
            result = await
                context.ApiResources
                .Include(x => x.Scopes)
                .Include(x => x.UserClaims)
                .FirstOrDefaultAsync(x => x.Id == id);
        }

        return result;
    }
}

我创建 Mock 对象的尝试如下：

Mock<IServiceProvider> serviceProvider = new Mock<IServiceProvider>();

serviceProvider.Setup(x => x.GetRequiredService<ConfigurationDbContext>())
    .Returns(new ConfigurationDbContext(Options, StoreOptions));

Mock<IServiceScope> serviceScope = new Mock<IServiceScope>();

serviceScope.Setup(x => x.ServiceProvider).Returns(serviceProvider.Object);

serviceProvider.Setup(x => x.CreateScope()).Returns(serviceScope.Object);

我收到以下错误：

System.NotSupportedException : Expression references a method that does not belong to the mocked object: x => x.GetRequiredService()

Answer 1

如前所述，Moq 不允许设置扩展方法。

在这种情况下，上述扩展方法的源代码可在 Github

上找到

ServiceProviderServiceExtensions.

解决此类问题的通常方法是找出扩展方法的作用并通过其执行安全地模拟路径。

所有这些中的基本类型是 IServiceProvider 及其 object Getservice(Type type) 方法。此方法是解析服务类型时最终调用的方法。而且我们只处理抽象（接口），这使得最小起订量的使用变得更加容易。

//Arrange
var serviceProvider = new Mock<IServiceProvider>();
serviceProvider
    .Setup(x => x.GetService(typeof(ConfigurationDbContext)))
    .Returns(new ConfigurationDbContext(Options, StoreOptions));

var serviceScope = new Mock<IServiceScope>();
serviceScope.Setup(x => x.ServiceProvider).Returns(serviceProvider.Object);

var serviceScopeFactory = new Mock<IServiceScopeFactory>();
serviceScopeFactory
    .Setup(x => x.CreateScope())
    .Returns(serviceScope.Object);

serviceProvider
    .Setup(x => x.GetService(typeof(IServiceScopeFactory)))
    .Returns(serviceScopeFactory.Object);

var sut = new ApiResourceRepository(serviceProvider.Object);

//Act
var actual = sut.Get(myIntValue);

//Asssert
//...

查看上面的代码，您会看到该安排如何满足扩展方法的预期行为以及扩展（没有双关语意）被测方法。

Answer 2

我也在找这个，但我只需要模拟 GetService。我总是使用 AutoFac 来自动生成模拟。在这个例子中 'GetService' 总是 returns 一个模拟实例。您可以在之后使用冻结方法更改模拟行为。

示例：

Class 测试：

public class ApiResourceRepository : ApiResourceRepository {
            private readonly IServiceProvider _serviceProvider;

            public ApiResourceRepository(IServiceProvider serviceProvider) {
                _serviceProvider = serviceProvider;
            }

            public object Get(int id) {
                using (var serviceScope = _serviceProvider.CreateScope()) {
                    var repo = serviceScope.ServiceProvider.GetService<IPersonRepository>();
                    return repo.GetById(id);
                }
            }
        }

单元测试：

 [Fact]
        public void Test() {
            // arrange
            var fixture = new Fixture()
             .Customize(new AutoMoqCustomization())
             .Customize(new ServiceProviderCustomization());

            fixture.Freeze<Mock<IPersonRepository>>()
                .Setup(m => m.GetById(It.IsAny<int>()))
                .Returns(new Person(Name = "John"));

            // Act
            var apiResource = _fixture.Create<ApiResourceRepository>();
            var person = apiResource.Get(1);

            // Assert
            ...
        }

自定义 AutoFac 提供程序

public class ServiceProviderCustomization : ICustomization {

        public void Customize(IFixture fixture) {
            var serviceProviderMock = fixture.Freeze<Mock<IServiceProvider>>();

            // GetService
            serviceProviderMock
               .Setup(m => m.GetService(It.IsAny<Type>()))
               .Returns((Type type) => {
                   var mockType = typeof(Mock<>).MakeGenericType(type);
                   var mock = fixture.Create(mockType, new SpecimenContext(fixture)) as Mock;

                   // Inject mock again, so the behavior can be changed with _fixture.Freeze()
                   MethodInfo method = typeof(FixtureRegistrar).GetMethod("Inject");
                   MethodInfo genericMethod = method.MakeGenericMethod(mockType);
                   genericMethod.Invoke(null, new object[] { fixture, mock });

                   return mock.Object;
               });

            // Scoped
            var serviceScopeMock = fixture.Freeze<Mock<IServiceScope>>();
            serviceProviderMock
               .As<IServiceScopeFactory>()
               .Setup(m => m.CreateScope())
               .Returns(serviceScopeMock.Object);

            serviceProviderMock.As<ISupportRequiredService>()
                .Setup(m => m.GetRequiredService(typeof(IServiceScopeFactory)))
                .Returns(serviceProviderMock.Object);
        }
    }

Answer 3

我想争辩说，当您需要添加那么多仪式来模拟一个简单的方法时，那么您的代码可能不是很容易测试。因此，另一种选择是将服务定位器隐藏在一个更加测试和模拟友好的界面后面（在我看来也是一个更好的界面）：

public interface IServiceLocator : IDisposable
{
    T Get<T>();
}

public class ScopedServiceLocator : IServiceLocator
{
    private readonly IServiceScopeFactory _factory;
    private IServiceScope _scope;

    public ScopedServiceLocator(IServiceScopeFactory factory)
    {
        _factory = factory;
    }

    public T Get<T>()
    {
        if (_scope == null)
            _scope = _factory.CreateScope();

        return _scope.ServiceProvider.GetService<T>();
    }


    public void Dispose()
    {
        _scope?.Dispose();
        _scope = null;
    }
}

我在这里只实现了 GetService<T> 方法，但您可以轻松 add/remove 以便定位器更好地满足您的需要。以及如何使用它的示例；

public class ALongRunningTask : IRunForALongTime
{
    private readonly IServiceLocator _serviceLocator;

    public ALongRunningTask(IServiceLocator serviceLocator)
    {
        _serviceLocator = serviceLocator;
    }

    public void Run()
    {
        using (_serviceLocator)
        {
            var repository = _serviceLocator.Get<IRepository>();
        }
    }
}

Answer 4

免责声明：嵌入式链接指向我的 GitHub 和 NuGet 页面的子页面。但我希望它能帮助到你或其他人。

我刚刚创建了这样的东西，因为我找不到任何东西。它实现 IServiceCollection 和 IServiceProvider 来测试我的 Startup-Configuration，特别是，是否所有类型都正确注册到 DI-Container。它是这些接口的通用替代品，为每个注册类型提供 Mocks (Moq) 作为单例。 Foo 不同于 Foo。

GitHub上有个readme.md，代码库也没有那么大。

还有一个nuget package called MockProvider and - as mentioned - the code is on GitHub。我把它放在麻省理工学院下，所以用它做你想做的事。它可以免费使用和贡献。

将其视为一种回馈方式。

Answer 5

一般规则是您不要模拟不属于您的类型。除非您需要验证对服务提供商的调用，否则只需在测试中从 ServiceCollection 构建 IServiceProvider。

Answer 6

我使用 Moq 和 xUnit 进行测试。我之前运行遇到过类似的问题，我的解决方案是将数据 t运行sactions 提取到带有接口的 SqlExecuter class 中，这样我就可以直接模拟来自数据库的响应。这足以简化一切，足以构建服务提供者并将其传递进去。您将需要 xUnit、Moq 和一些 Microsoft 软件包（Microsoft.EntityFrameworkCore & Microsoft.EntityFrameworkCore.InMemory）。

SqlExecuter.cs

public interface ISqlExecuter
{
    Task<List<SqlParameter>> FirstOrDefaultApiResource(ConfigurationDbContext context, int id);
}

public class SqlExecuter : ISqlExecuter
{
    public async Task<ApiResource> FirstOrDefaultApiResource(ConfigurationDbContext context, int id) =>
        return await context.ApiResources
            .Include(x => x.Scopes)
            .Include(x => x.UserClaims)
            .FirstOrDefaultAsync(x => x.Id == id);
}

ApiResourceRepository.cs

public class ApiResourceRepository : IApiResourceRepository
{
    private readonly IServiceProvider _serviceProvider;
    private readonly ISqlExecuter _sqlExecuter;

    public ApiResourceRepository(IServiceProvider serviceProvider, ISqlExecuter sqlExecuter)
    {
        _serviceProvider = serviceProvider;
        _sqlExecuter = sqlExecuter;
        _dbSettings = dbSettings;
    }

    public async Task<ApiResource> Get(int id)
    {
        ApiResource result;

        using (var serviceScope = _serviceProvider.GetRequiredService<IServiceScopeFactory>().CreateScope())
        {
            var context = serviceScope.ServiceProvider.GetRequiredService<ConfigurationDbContext>();
            result = await _sqlExecuter.FirstOrDefaultApiResource(context, id);
        }

        return result;
    }
}

ApiResourceRepositoryTests.cs

[Fact]
public async Task Get_Success()
{
    // Arrange
    var id = 42069;
    var scope = "Scope";
    var claim = "UserClaims";
    var services = new ServiceCollection();
    services.AddDbContext<ConfigurationDbContext>(opt => opt
            .UseInMemoryDatabase(databaseName: $"ConfigurationDbContext-{ DateTime.Now.ToString() }")
            .ConfigureWarnings(x => x.Ignore(InMemoryEventId.TransactionIgnoredWarning)),
        ServiceLifetime.Singleton, ServiceLifetime.Singleton);
    var serviceProvider = services.BuildServiceProvider();
    var mockSqlExecuter = new Mock<SqlExecuter>();
    mockSqlExecuter.Setup(x => x.FirstOrDefaultApiResource(It.IsAny<ConfigurationDbContext>(), It.IsAny<int>()))
        .Returns(new ApiResource() { Id = id , Scope = scope, UserClaims = claim })
    var mockApiResourceRepository = new Mock<ApiResourceRepository>(serviceProvider, mockSqlExecuter.Object);

    // Act
    var result = await mockApiResourceRepository.Object.Get(id);

    
    // Assert
    Assert.NotNull(response);
    Assert.Equal(id, result.Id);
    Assert.Equal(scope, result.Scope);
    Assert.Equal(claim, result.UserClaims);
}

或者不使用 SqlExecuter class，在其他情况下，我已经在服务提供商中设置了上下文。

// Arrange
var id = 42069;
var scope = "Scope";
var claim = "UserClaims";
var services = new ServiceCollection();
services.AddDbContext<ConfigurationDbContext>(opt => opt
        .UseInMemoryDatabase(databaseName: $"ConfigurationDbContext-{DateTime.Now.ToString()}")
        .ConfigureWarnings(x => x.Ignore(InMemoryEventId.TransactionIgnoredWarning)),
    ServiceLifetime.Singleton, ServiceLifetime.Singleton);
var serviceProvider = services.BuildServiceProvider();
var context = Interfaces.ServiceProvider.GetService<ComQueMDSContext>();
context.ApiResources.RemoveRange(context.ApiResources);
context.ApiResources.AddRange(new List<ApiResource>(){ new ApiResource(){ Id = id, Scope = scope, UserClaims = claim } });
context.SaveChanges();
var mockApiResourceRepository = new Mock<ApiResourceRepository>(serviceProvider);

我还将大部分工作提取到夹具 class 和集合中，正如 xUnit 所建议的那样集中上下文并减少测试时间。

https://xunit.net/docs/shared-context

Answer 7

以防万一它对某人有用，下面是一个示例，说明我如何按照建议为我的单元测试创建自己的 ServiceProvider。我还添加了 ServiceScope 和 ServiceScopeFactory 模拟来为它提供服务。

这是我的单元测试中的代码：

var serviceCollection = new ServiceCollection();

// Add any DI stuff here:
serviceCollection.AddSingleton<ILogger>(loggerMock.Object);

// Create the ServiceProvider
var serviceProvider = serviceCollection.BuildServiceProvider();

// serviceScopeMock will contain my ServiceProvider
var serviceScopeMock = new Mock<IServiceScope>();
serviceScopeMock.SetupGet<IServiceProvider>(s => s.ServiceProvider)
    .Returns(serviceProvider);

// serviceScopeFactoryMock will contain my serviceScopeMock
var serviceScopeFactoryMock = new Mock<IServiceScopeFactory>();
serviceScopeFactoryMock.Setup(s => s.CreateScope())
    .Returns(serviceScopeMock.Object);

然后我可以将我的 serviceScopeFactoryMock 传递给我的 sut 构造函数。

这是正在测试的代码：

using (var scope = _serviceScopeFactory.CreateScope())
{
    var logger = scope.ServiceProvider.GetRequiredService<ILogger>();
    ...
}

Answer 8

这是我在范围内的服务提供者中模拟的片段。用于测试 IHostedService 等：

Mock<IServiceProvider> CreateScopedServicesProvider(params (Type @interface, Object service)[] services)
{
    var scopedServiceProvider = new Mock<IServiceProvider>();

    foreach (var (@interfcae, service) in services)
    {
        scopedServiceProvider
            .Setup(s => s.GetService(@interfcae))
            .Returns(service);
    }

    var scope = new Mock<IServiceScope>();
    scope
        .SetupGet(s => s.ServiceProvider)
        .Returns(scopedServiceProvider.Object);

    var serviceScopeFactory = new Mock<IServiceScopeFactory>();
    serviceScopeFactory
        .Setup(x => x.CreateScope())
        .Returns(scope.Object);

    var serviceProvider = new Mock<IServiceProvider>();
    serviceProvider
        .Setup(s => s.GetService(typeof(IServiceScopeFactory)))
        .Returns(serviceScopeFactory.Object);

    return serviceProvider;
}

用法：

var service = new Mock<IMyService>();
var serviceProvider = CreateScopedServicesProvider((typeof(IMyService), scopedService.Object));
var sut = new ServiceThatUsesScopes(serviceProvider.Object)

最小起订量 IServiceProvider / IServiceScope

Moq IServiceProvider / IServiceScope

c#

unit-testing

moq

.net-core

asp.net-core