xUnit Custom Attributes – BeforeAfterTestAttribute

xUnit is great!  If you haven’t used it yet it really is well worth the time to explore and get to grips with.  I was recently creating some Serialization tests using the WCF DataContractSerializer.  In order to make sure the test were all as I wanted/expected and to have a clean slate between each serialization test it is prudent to ensure the files generated by the tests are cleaned up afterwards.  Here is a little class that provides exactly this through the use of a custom attribute.  This also means that your test code isn’t polluted with unneccessary code clutter … neat!

Here is the class:

public class SerializationCleanupAttribute : BeforeAfterTestAttribute
{
    public readonly string FileToCleanUp;

    public SerializationCleanupAttribute(string fileToCleanUp)
    {
        FileToCleanUp = fileToCleanUp;
    }

    public override void Before(System.Reflection.MethodInfo methodUnderTest)
    {
        if (File.Exists(FileToCleanUp))
        {
            File.Delete(FileToCleanUp);
        }
    }

    public override void After(System.Reflection.MethodInfo methodUnderTest)
    {
        if (File.Exists(FileToCleanUp))
        {
            File.Delete(FileToCleanUp);
        }
    }
}

Here is a test using the class:

[Fact]
[SerializationCleanup(FileName)]
public void TestClientConfigSerialization()
{
    ClientEndpointConfiguration config = new ClientEndpointConfiguration();
    config.CloseTimeout = new TimeSpan(0, 10, 0);
    config.EndpointName = "Default";
    config.EndpointNamespace = "http://jammer.biz/namespace/test/";
    config.StoreToDisk(FileName);
    Assert.True(File.Exists(FileName));
}