使用泛型的xUnit理论测试 [英] xUnit theory test using generics

问题描述

在xUnit中，我可以进行Theory测试，该测试使用以下形式的泛型:

In xUnit I can have a Theory test that uses generics in this form:

[Theory]
[MemberData(SomeScenario)]
public void TestMethod<T>(T myType)
{
    Assert.Equal(typeof(double), typeof(T));
}

public static IEnumerable<object[]> SomeScenario()
{
    yield return new object[] { 1.23D };
}

这将给我通用的T参数作为double.是否可以使用MemberData为具有如下签名的测试指定通用类型参数:

Which will give me the generic T parameter as double. Is it possible to use MemberData to specify the generic type parameter for a test with a signature like:

[Theory]
[MemberData(SomeTypeScenario)]
public void TestMethod<T>()
{
    Assert.Equal(typeof(double), typeof(T));
}

如果使用MemberData或任何其他提供的属性(我怀疑不是)是不可能的，是否可以为Xunit创建可以实现此目的的属性?可能类似于在场景方法中指定类型并使用反射的方式类似于Jon Skeet在这里的答案: C#中的泛型，使用变量的类型作为参数

If it is not possible with MemberData or any other provided attribute (which I'm suspecting that it isn't), is it possible to create an attribute for Xunit that can achieve this? Maybe something along the lines of specifying Types in the Scenarios method and using reflection in a similar manner to Jon Skeet's answer here: Generics in C#, using type of a variable as parameter

推荐答案

您可以简单地将Type用作输入参数.例如:

You can simply include Type as an input parameter instead. E.g.:

[Theory]
[MemberData(SomeTypeScenario)]
public void TestMethod(Type type) {
  Assert.Equal(typeof(double), type);
}

public static IEnumerable<object[]> SomeScenario() {
  yield return new object[] { typeof(double) };
}

xunit上不需要使用泛型.

There is no need to go with generics on xunit.

编辑(如果您确实需要通用)

1)您需要将ITestMethod子类化以保留通用方法信息，它还必须实现IXunitSerializable

1) You need to subclass ITestMethod to persist generic method info, it also has to implement IXunitSerializable

// assuming namespace Contosco
public class GenericTestMethod : MarshalByRefObject, ITestMethod, IXunitSerializable
{
    public IMethodInfo Method { get; set; }
    public ITestClass TestClass { get; set; }
    public ITypeInfo GenericArgument { get; set; }

    /// <summary />
    [Obsolete("Called by the de-serializer; should only be called by deriving classes for de-serialization purposes")]
    public GenericTestMethod()
    {
    }

    public GenericTestMethod(ITestClass @class, IMethodInfo method, ITypeInfo genericArgument)
    {
        this.Method = method;
        this.TestClass = @class;
        this.GenericArgument = genericArgument;
    }

    public void Serialize(IXunitSerializationInfo info)
    {
        info.AddValue("MethodName", (object) this.Method.Name, (Type) null);
        info.AddValue("TestClass", (object) this.TestClass, (Type) null);
        info.AddValue("GenericArgumentAssemblyName", GenericArgument.Assembly.Name);
        info.AddValue("GenericArgumentTypeName", GenericArgument.Name);
    }

    public static Type GetType(string assemblyName, string typeName)
    {
#if XUNIT_FRAMEWORK    // This behavior is only for v2, and only done on the remote app domain side
        if (assemblyName.EndsWith(ExecutionHelper.SubstitutionToken, StringComparison.OrdinalIgnoreCase))
            assemblyName = assemblyName.Substring(0, assemblyName.Length - ExecutionHelper.SubstitutionToken.Length + 1) + ExecutionHelper.PlatformSuffix;
#endif

#if NET35 || NET452
        // Support both long name ("assembly, version=x.x.x.x, etc.") and short name ("assembly")
        var assembly = AppDomain.CurrentDomain.GetAssemblies().FirstOrDefault(a => a.FullName == assemblyName || a.GetName().Name == assemblyName);
        if (assembly == null)
        {
            try
            {
                assembly = Assembly.Load(assemblyName);
            }
            catch { }
        }
#else
        System.Reflection.Assembly assembly = null;
        try
        {
            // Make sure we only use the short form
            var an = new AssemblyName(assemblyName);
            assembly = System.Reflection.Assembly.Load(new AssemblyName { Name = an.Name, Version = an.Version });

        }
        catch { }
#endif

        if (assembly == null)
            return null;

        return assembly.GetType(typeName);
    }

    public void Deserialize(IXunitSerializationInfo info)
    {
        this.TestClass = info.GetValue<ITestClass>("TestClass");
        string assemblyName = info.GetValue<string>("GenericArgumentAssemblyName");
        string typeName = info.GetValue<string>("GenericArgumentTypeName");
        this.GenericArgument = Reflector.Wrap(GetType(assemblyName, typeName));
        this.Method = this.TestClass.Class.GetMethod(info.GetValue<string>("MethodName"), true).MakeGenericMethod(GenericArgument);
    }
}

2)您需要为通用方法编写自己的发现程序，它必须是IXunitTestCaseDiscoverer

2) You need to write your own discoverer for generic methods, it has to be subclass of IXunitTestCaseDiscoverer

// assuming namespace Contosco
public class GenericMethodDiscoverer : IXunitTestCaseDiscoverer
{
    public GenericMethodDiscoverer(IMessageSink diagnosticMessageSink)
    {
        DiagnosticMessageSink = diagnosticMessageSink;
    }

    protected IMessageSink DiagnosticMessageSink { get; }

    public IEnumerable<IXunitTestCase> Discover(ITestFrameworkDiscoveryOptions discoveryOptions,
        ITestMethod testMethod, IAttributeInfo factAttribute)
    {
        var result = new List<IXunitTestCase>();
        var types = factAttribute.GetNamedArgument<Type[]>("Types");
        foreach (var type in types)
        {
            var typeInfo = new ReflectionTypeInfo(type);
            var genericMethodInfo = testMethod.Method.MakeGenericMethod(typeInfo);
            var genericTestMethod = new GenericTestMethod(testMethod.TestClass, genericMethodInfo, typeInfo);

            result.Add(
                new XunitTestCase(DiagnosticMessageSink, discoveryOptions.MethodDisplayOrDefault(),
                    genericTestMethod));
        }

        return result;
    }
}

3)最后，您可以为通用方法设置属性，并通过XunitTestCaseDiscoverer属性将其挂钩到自定义发现程序

3) Finally you can make your attribute for generic methods and hook it to your custom discoverer by XunitTestCaseDiscoverer attribute

// assuming namespace Contosco
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
[XunitTestCaseDiscoverer("Contosco.GenericMethodDiscoverer", "Contosco")]
public sealed class GenericMethodAttribute : FactAttribute
{
    public Type[] Types { get; private set; }

    public GenericMethodAttribute(Type[] types)
    {
        Types = types;
    }
}

用法:

[GenericMethod(new Type[] { typeof(double), typeof(int) })]
public void TestGeneric<T>()
{
  Assert.Equal(typeof(T), typeof(double));
}

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