unit-testing - 如何重置 autofac 容器？

Question

在我的测试中，我设置了一个 autofac 容器，它返回一些实际实现和一些模拟(数据库、外部系统)。

问题是，每次测试后我都会处理容器并创建一个新容器: Autofac.IContainer.Dispose()和Container = builder.Build(); 已经注册的实例仍然存在。

如何重置容器，使其再次“像新的一样”？

我想要这样做的原因是 - 我想用另一个模拟实例替换一个模拟实例。它正在注册为 Singleton。

----编辑

感谢您的回答。我决定添加更多代码并描述我实际上想要实现的目标。但这实际上是另一个主题(可能已经回答了问题 - 单元测试 CQRS)。

我的应用程序包含静态 IContainer 属性:

public static IContainer Container { get; private set; }

每次测试执行后，我都会通过调用这两个方法再次创建它:

public static ContainerBuilder Compose(IEnumerable<DependencyProvider> dependencyProviders)
{
    var collection = dependencyProviders as List<DependencyProvider> ?? dependencyProviders.ToList();
    var included = new HashSet<DependencyProvider>(collection);
    var includedTypes = new HashSet<Type>(collection.Select(x => x.GetType()));
    var currentWorkingSet = new List<DependencyProvider>(collection);

    while (true)
    {
        var candidates = currentWorkingSet.SelectMany(x => x.GetDependencies());
        var typesToBeAdded = candidates.Where(x => !includedTypes.Contains(x)).Distinct().ToList();
        if (typesToBeAdded.Any() == false)
            break;

       currentWorkingSet.Clear();
       foreach (var type in typesToBeAdded)
       {
            includedTypes.Add(type);
            var instance = CreateInstance(type);
            included.Add(instance);
            currentWorkingSet.Add(instance);
       }
    }

return BuildContainer(included);
}

和

TestDependencyProvider dependencyProvider = new TestDependencyProvider()
var builder = Compose(new[] { dependencyProvider });
Container = builder.Build();

TestDependencyProvider为每个测试创建并包含 moqed 实例。它注册这些模拟和 x.GetDependencies()使用原始容器注册，即 container.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()).AsClosedTypesOf(typeof(IAggregateBusinessRuleForEvent<,>));

我最感兴趣的类型是 IAggregateBusinessRuleForEvent<,>) 的实现之一。

public class RuleA: IAggregateBusinessRuleForEvent<AEvent, Something>
{
    private readonly IDependency _dependency;

    public RejectCompanyNameRule(IDependency dependency)
    {
         _dependency = dependency;
    }
}

所以即使我再次创建这个容器 RuleA仍然在那里，我的所有测试都使用具有相同 _dependency 的相同实例:/

仍然不完全清楚为什么代码看起来像它的样子，我试图通过添加测试来理解它......

--------编辑2

按照吉米的建议，我使用 Update 实现了一个示例我

public interface IExample<T>
{
    void Hello();
}

public interface IExampleDependecy
{
    void SaySomething();
}

public class Example : IExample<string>
{
    private IExampleDependecy _dependecy;

    public Example(IExampleDependecy dependecy)
    {
        _dependecy = dependecy;
    }

    public void Hello()
    {
        Console.WriteLine("Hello");
        _dependecy.SaySomething();
    }
}

[TestMethod]
public void T()
{
    // first test
    var builder = new ContainerBuilder();
    builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()).AsClosedTypesOf(typeof(IExample<>));
    var mockA = new Moq.Mock<IExampleDependecy>();
    mockA.Setup(d => d.SaySomething()).Callback(() => Console.WriteLine("A"));

    builder.RegisterInstance(mockA.Object).SingleInstance();
    var container = builder.Build();

    var sample1 = container.Resolve<IExample<string>>();
    sample1.Hello();



    // new test using same container
    var updater = new ContainerBuilder();
    builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()).AsClosedTypesOf(typeof(IExample<>));
    var mockB = new Moq.Mock<IExampleDependecy>();
    mockB.Setup(d => d.SaySomething()).Callback(() => Console.WriteLine("B"));
    builder.RegisterInstance(mockB.Object).SingleInstance();
    updater.Update(container); // overwrites existing registrations

    var sample2 = container.Resolve<IExample<string>>();
    sample2.Hello();
}

结果是:

Hello
A
Hello
A

Answer 1

默认情况下，Autofac 会用后续注册覆盖之前的注册。这意味着除了使用新实例更新容器之外，您无需执行任何特殊操作:

var builder = new ContainerBuilder();
builder.RegisterInstance(new Sample("A")).SingleInstance();
var container = builder.Build();
var sample = container.Resolve<Sample>();
// do your test

...

// new test using same container
var updater = new ContainerBuilder();
updater.RegisterInstance(new Sample("B")).SingleInstance();
updater.Update(container); // overwrites existing registrations
var sample = container.Resolve<Sample>(); // returns "B"