xUnit.Net – Running the tests (TestCategory)

In my previous post I showed an example about converting a MSTest class to xUnit.Net, and now I want to provide a solution for converting MSTest TestCategory attribute to an equivalent implementation in xUnit.Net.

MSTest allowed us to run the test that belongs to an specific category, let’s see a solution on how this can be accomplished in xUnit.Net.

using Xunit;
using Xunit.Extensions;

namespace xUnitCustomizations
{
    [CustomTestClassCommand]
    public class TestClass
    {
        [Fact, TestCategory("Unit")]
        public void FastTest()
        {
            Debug.WriteLine("fast test executed");
            Assert.True(true);
        }

        [Fact, TestCategory("Integration")]
        public void SlowTest()
        {
            Thread.Sleep(5000);
            Debug.WriteLine("slow test executed");
            Assert.True(true);
        }
    }
}

Create TestCategory attribute

 

namespace Xunit.Extensions
{
    public class TestCategoryAttribute : TraitAttribute
    {
        public TestCategoryAttribute(string category)
        : base("TestCategory", category) { }
    }
    ...
}

CustomTestClassCommandAttribute attribute is used to indicate that a custom test runner will be used

public class CustomTestClassCommandAttribute : RunWithAttribute
{
    public CustomTestClassCommandAttribute() : base(typeof(CustomTestClassCommand)) { }
}

CustomTestClassCommand  is the class that implements ITestClassCommand and acts as the runner for the test fixture

public class CustomTestClassCommand : ITestClassCommand
{
    // Delegate most of the work to the existing TestClassCommand class so that we
    // can preserve any existing behavior (like supporting IUseFixture<T>).
    readonly TestClassCommand cmd = new TestClassCommand();

    #region ITestClassCommand Members
    public object ObjectUnderTest
    {
        get { return cmd.ObjectUnderTest; }
    }

    public ITypeInfo TypeUnderTest
    {
        get { return cmd.TypeUnderTest; }
        set { cmd.TypeUnderTest = value; }
    }

    public int ChooseNextTest(ICollection<IMethodInfo> testsLeftToRun)
    {
        return cmd.ChooseNextTest(testsLeftToRun);
    }

    public Exception ClassFinish()
    {
        return cmd.ClassFinish();
    }

    public Exception ClassStart()
    {
        return cmd.ClassStart();
    }

    public IEnumerable<ITestCommand> EnumerateTestCommands(IMethodInfo testMethod)
    {
        return cmd.EnumerateTestCommands(testMethod);
    }

    public bool IsTestMethod(IMethodInfo testMethod)
    {
        return cmd.IsTestMethod(testMethod);
    }

    public IEnumerable<IMethodInfo> EnumerateTestMethods()
    {
        string category;

        foreach (IMethodInfo method in cmd.EnumerateTestMethods())
        {
            category = string.Empty;
            foreach (IAttributeInfo attr in method.GetCustomAttributes(typeof(TestCategoryAttribute)))
                category = attr.GetPropertyValue<string>("Value");

            if (category.ToLower().Contains("unit")) // We can make this configurable
                yield return method;
        }
    }
    #endregion
}

The Method public IEnumerable<IMethodInfo> EnumerateTestMethods() filters the tests methods by TestCategory's attribute Value, note that we can make this configurable so we can configure our CI server to run unit test as soon as there are changes in the repository to provide quick feedback and schedule (e.g. once a day) the execution slower test like integration or Web UI test.