Question

我有一个我试图测试的引导程序对象（使用xunit）。测试似乎已经过去了，但我在其中一个测试跑步者（ncrunch）中看到了一些奇怪的东西。我同时使用ncrunch和resharper xunit runner。我的想法是采用单例所在的程序集，将其加载到新的appdomain中，使用反射运行我的测试，然后卸载app域。正如我所说，测试传递了ncrunch和resharper，但是ncrunch没有显示我期望的执行路径。这是代码：

public class Bootstrapper
{
    private static Bootstrapper booted;

    public Bootstrapper()
    {
        // performs boot tasks
    }

    public static void Boot()
    {
        if (booted == null)
        {
            var staticboot = new Bootstrapper();
            Booted = staticboot;
        }
    }

    public static Bootstrapper Booted
    {
        get
        {
            if (booted == null) throw new InvalidOperationException("Should call Boot() before accessing the booted object");
            return booted;
        }
        set { booted = value; }
    }
}

public class Tests
{
    [Fact]
    public void TryingToAccessBootedKernelBeforeBootThrowsException()
    {
        var setup = this.SetupTestingDomainWithAssembly("StackOverflowQuestion.Tests.dll");
        var kernelType = setup.Item2.GetType("StackOverflowQuestion.Tests.Bootstrapper");
        var bootedkernelProperty = kernelType.GetProperty("Booted");
        try
        {
            bootedkernelProperty.GetValue(null);
        }
        catch (Exception e)
        {
            Assert.IsType(typeof(InvalidOperationException), e.InnerException);
        }

        AppDomain.Unload(setup.Item1);
    }

    [Fact]
    public void CanAccessKernelAfterBooting()
    {
        var setup = this.SetupTestingDomainWithAssembly("StackOverflowQuestion.Tests.dll");
        var kernelType = setup.Item2.GetType("StackOverflowQuestion.Tests.Bootstrapper");
        var bootMethod = kernelType.GetMethod("Boot");
        bootMethod.Invoke(null, new object[] { });
        var bootedkernelProperty = kernelType.GetProperty("Booted");

        Assert.DoesNotThrow(() => bootedkernelProperty.GetValue(null));

        AppDomain.Unload(setup.Item1);
    }

    [Fact]
    public void BootIsIdempotent()
    {
        var setup = this.SetupTestingDomainWithAssembly("StackOverflowQuestion.Tests.dll");
        var kernelType = setup.Item2.GetType("StackOverflowQuestion.Tests.Bootstrapper");
        var bootMethod = kernelType.GetMethod("Boot");
        bootMethod.Invoke(null, new object[] {});
        var bootedkernelProperty = kernelType.GetProperty("Booted");

        var bootedKernel = (Bootstrapper)bootedkernelProperty.GetValue(null);

        bootMethod.Invoke(null, new object[] {});

        var secondCall = (Bootstrapper)bootedkernelProperty.GetValue(null);

        Assert.Equal(bootedKernel, secondCall);

        AppDomain.Unload(setup.Item1);
    }

    private Tuple<AppDomain, Assembly> SetupTestingDomainWithAssembly(string assemblyPath)
    {
        // we guarantee that each domain will have a unique name.
        AppDomain testingDomain = AppDomain.CreateDomain(DateTime.Now.Ticks.ToString());
        var pancakesAssemblyName = new AssemblyName();
        pancakesAssemblyName.CodeBase = assemblyPath;
        var assembly = testingDomain.Load(pancakesAssemblyName);

        return new Tuple<AppDomain, Assembly>(testingDomain, assembly);
    }
}

现在，我认识到需要在代码方面进行一些清理，但我很高兴看到它们都是绿色的。如果我摆弄它们使它们失败，那就按预期工作了。唯一有点臭的是，ncrunch报告了奇怪的执行路径。具体来说，ncrunch表明从不执行抛出无效操作异常的行。

我认为在处理其他应用程序域时，ncrunch可能存在错误，但我更有可能实际上不了解应用程序域的内容，但我不确定从何处继续这里。

另外，我确实知道单身人士很糟糕，但我相信bootstrappers是他们实际上有用的地方。你想保证它们只被启动一次。

Answer 1

除非我在这里遗漏了一些东西......看起来你实际上并没有在你的其他app域中调用任何东西。您的反映发生在当前的应用领域。看一下DoCallback方法：http://msdn.microsoft.com/en-us/library/system.appdomain.docallback.aspx

public class Tests
{
    [Fact]
    public void TryingToAccessBootedKernelBeforeBootThrowsException()
    {
        var appDomain = AppDomain.Create(Guid.NewGuid());
        try
        {
            appDomain.DoCallBack(new CrossAppDomainDelegate(TryingToAccessBootedKernelBeforeBootThrowsException_AppDomainCallback));
        }
        catch (Exception e)
        {
            Assert.IsType(typeof(InvalidOperationException), e.InnerException);
        }

        AppDomain.Unload(appDomain);
    }

    public static void TryingToAccessBootedKernelBeforeBootThrowsException_AppDomainCallback()
    {
        var bootstrapper = BootStrapper.Booted;
    }
}

这些Singleton单元测试是否真的按预期工作？

1 个答案: