NUnit TestCase with Generics

Question

有没有办法将使用TestCase的泛型类型传递给NUnit中的测试？

这是我想做的但语法不正确...

[Test]
[TestCase<IMyInterface, MyConcreteClass>]
public void MyMethod_GenericCall_MakesGenericCall<TInterface, TConcreteClass>()
{
    // Arrange

    // Act
    var response = MyClassUnderTest.MyMethod<TInterface>();

    // Assert
    Assert.IsInstanceOf<TConcreteClass>(response);
}

或者如果没有,实现相同功能的最佳方法是什么(显然我在实际代码中会有多个TestCases)？

用另一个例子更新......

这是传递单个泛型类型的另一个示例...

[Test]
[TestCase<MyClass>("Some response")]
public void MyMethod_GenericCall_MakesGenericCall<T>(string expectedResponse)
{
    // Arrange

    // Act
    var response = MyClassUnderTest.MyMethod<T>();

    // Assert
    Assert.AreEqual(expectedResponse, response);
}

Answer 1

NUnit测试方法实际上可以是通用的,只要可以从参数推断泛型类型参数:

[TestCase(42)]
[TestCase("string")]
[TestCase(double.Epsilon)]
public void GenericTest<T>(T instance)
{
    Console.WriteLine(instance);
}

如果无法推断泛型参数,则测试运行器将不知道如何解析类型参数:

[TestCase(42)]
[TestCase("string")]
[TestCase(double.Epsilon)]
public void GenericTest<T>(object instance)
{
    Console.WriteLine(instance);
}

但在这种情况下,您可以实现自定义属性:

[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
public class TestCaseGenericAttribute : TestCaseAttribute, ITestBuilder
{
    public TestCaseGenericAttribute(params object[] arguments)
        : base(arguments)
    {
    }

    public Type[] TypeArguments { get; set; }

    IEnumerable<TestMethod> ITestBuilder.BuildFrom(IMethodInfo method, Test suite)
    {
        if (!method.IsGenericMethodDefinition)
            return base.BuildFrom(method, suite);

        if (TypeArguments == null || TypeArguments.Length != method.GetGenericArguments().Length)
        {
            var parms = new TestCaseParameters { RunState = RunState.NotRunnable };
            parms.Properties.Set("_SKIPREASON", $"{nameof(TypeArguments)} should have {method.GetGenericArguments().Length} elements");
            return new[] { new NUnitTestCaseBuilder().BuildTestMethod(method, suite, parms) };
        }

        var genMethod = method.MakeGenericMethod(TypeArguments);
        return base.BuildFrom(genMethod, suite);
    }
}

用法:

[TestCaseGeneric("Some response", TypeArguments = new[] { typeof(IMyInterface), typeof(MyConcreteClass) }]
public void MyMethod_GenericCall_MakesGenericCall<T1, T2>(string expectedResponse)
{
    // whatever
}

以及类似的定制TestCaseSourceAttribute:

[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
public class TestCaseSourceGenericAttribute : TestCaseSourceAttribute, ITestBuilder
{
    public TestCaseSourceGenericAttribute(string sourceName)
        : base(sourceName)
    {
    }

    public Type[] TypeArguments { get; set; }

    IEnumerable<TestMethod> ITestBuilder.BuildFrom(IMethodInfo method, Test suite)
    {
        if (!method.IsGenericMethodDefinition)
            return base.BuildFrom(method, suite);

        if (TypeArguments == null || TypeArguments.Length != method.GetGenericArguments().Length)
        {
            var parms = new TestCaseParameters { RunState = RunState.NotRunnable };
            parms.Properties.Set("_SKIPREASON", $"{nameof(TypeArguments)} should have {method.GetGenericArguments().Length} elements");
            return new[] { new NUnitTestCaseBuilder().BuildTestMethod(method, suite, parms) };
        }

        var genMethod = method.MakeGenericMethod(TypeArguments);
        return base.BuildFrom(genMethod, suite);
    }
}

用法:

[TestCaseSourceGeneric(nameof(mySource)), TypeArguments = new[] { typeof(IMyInterface), typeof(MyConcreteClass) }]

Answer 2

今天我有机会做类似的事情,并且不满意使用反射.

我决定利用[TestCaseSource]代替将测试逻辑作为测试上下文委托给通用测试类,固定在非泛型接口上,并从各个测试中调用接口(我的实际测试在接口中有更多方法,并使用AutoFixture设置上下文):

class Sut<T>
{
    public string ReverseName()
    {
        return new string(typeof(T).Name.Reverse().ToArray());
    }
}

[TestFixture]
class TestingGenerics
{
    public IEnumerable<ITester> TestCases()
    {
        yield return new Tester<string> { Expectation = "gnirtS"};
        yield return new Tester<int> { Expectation = "23tnI" };
        yield return new Tester<List<string>> { Expectation = "1`tsiL" };
    }

    [TestCaseSource("TestCases")]
    public void TestReverse(ITester tester)
    {
        tester.TestReverse();
    }

    public interface ITester
    {
        void TestReverse();
    }

    public class Tester<T> : ITester
    {
        private Sut<T> _sut;

        public string Expectation { get; set; }

        public Tester()
        {
            _sut=new Sut<T>();
        }

        public void TestReverse()
        {
            Assert.AreEqual(Expectation,_sut.ReverseName());
        }

    }
}

Answer 3

我上周做了类似的事情。这就是我最终得到的结果：

internal interface ITestRunner
{
    void RunTest(object _param, object _expectedValue);
}

internal class TestRunner<T> : ITestRunner
{
    public void RunTest(object _param, T _expectedValue)
    {
        T result = MakeGenericCall<T>();

        Assert.AreEqual(_expectedValue, result);
    }
    public void RunTest(object _param, object _expectedValue)
    {
        RunTest(_param, (T)_expectedValue);
    }
}

然后是测试本身：

[Test]
[TestCase(typeof(int), "my param", 20)]
[TestCase(typeof(double), "my param", 123.456789)]
public void TestParse(Type _type, object _param, object _expectedValue)
{
    Type runnerType = typeof(TestRunner<>);
    var runner = Activator.CreateInstance(runnerType.MakeGenericType(_type));
    ((ITestRunner)runner).RunTest(_param, _expectedValue);
}

Answer 4

C#中的属性不能是通用的,因此您将无法完全按照您的意愿执行操作.也许最简单的方法是将TestCase属性放到一个使用反射来调用真实方法的辅助方法上.这样的东西可能会起作用(注意,未经测试):

    [TestCase(typeof(MyClass), "SomeResponse")]
    public void TestWrapper(Type t, string s)
    {
        typeof(MyClassUnderTest).GetMethod("MyMethod_GenericCall_MakesGenericCall").MakeGenericMethod(t).Invoke(null, new [] { s });
    }

Answer 5

您可以创建自定义GenericTestCaseAttribute

[Test]
[GenericTestCase(typeof(MyClass) ,"Some response", TestName = "Test1")]
[GenericTestCase(typeof(MyClass1) ,"Some response", TestName = "Test2")]
public void MapWithInitTest<T>(string expectedResponse)
{
    // Arrange

    // Act
    var response = MyClassUnderTest.MyMethod<T>();

    // Assert
    Assert.AreEqual(expectedResponse, response);
}

这是GenericTestCaseAttribute的实现

[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
public class GenericTestCaseAttribute : TestCaseAttribute, ITestBuilder
{
    private readonly Type _type;
    public GenericTestCaseAttribute(Type type, params object[] arguments) : base(arguments)
    {
        _type = type;
    }

    IEnumerable<TestMethod> ITestBuilder.BuildFrom(IMethodInfo method, Test suite)
    {
        if (method.IsGenericMethodDefinition && _type != null)
        {
            var gm = method.MakeGenericMethod(_type);
            return BuildFrom(gm, suite);
        }
        return BuildFrom(method, suite);
    }
}

Answer 6

首先从测试开始-即使在测试时。你想让我做什么？大概是这样的：

[Test]
public void Test_GenericCalls()
{
    MyMethod_GenericCall_MakesGenericCall<int>("an int response");
    MyMethod_GenericCall_MakesGenericCall<string>("a string response");
      :
}

然后，您可以将测试变成普通的旧功能测试。没有[测试]标记。

public void MyMethod_GenericCall_MakesGenericCall<T>(string expectedResponse)
{
    // Arrange

    // Act
    var response = MyClassUnderTest.MyMethod<T>();

    // Assert
    Assert.AreEqual(expectedResponse, response);
}