Adding metadata information to inside DataSourceGeneratorAttribute

[TheRumle]

I have a usecase where I have created a bunch of end to end test. I want to establish that my application supports different protocols and want to run the end to end test on the protocols. This can be done simply:

public sealed class ApplicationFixtureGeneratorAttribute<T> : DataSourceGeneratorAttribute<ApplicationFixture<T>>
    where T : notnull
{
    protected override IEnumerable<Func<ApplicationFixture<T>>> GenerateDataSources(DataGeneratorMetadata dataGeneratorMetadata)
    {
        //Is it possible to prepend all tests with the name of the protocol - sort of as a category
        foreach (var protocol in Enum.GetValues(typeof(WebProtocol)).Cast<WebProtocol>())
        {
            var serviceMatches = FindMatchingServices();
            foreach (var func in ApplicationFixtureIterator(serviceMatches, protocol))
            {
                yield return func;
            }
        }
    }
}

Is it possible to prepend the current tests' name with a category here?
What is the 'TUnit ideomatic' approach to dynamically working with the test metadata when it comes to manipulating the metadata? Do I approach this with TestContext.Current? This seems...harsh somewhat due to the lack of type information.

I am very very interested in the possibilities TUnit unlocks in terms of generating my own tests in a programmatic manner. It is something I have really been missing in XUnit.

[thomhurst]

A TestContext doesn't exist before generators are run, because the data generated will create new tests. So you'd have to go for a two phased approach.

The ObjectBag in the test builder context gets passed to the test context when eventually built.

Something like this in your data generator before you yield:

dataGeneratorMetadata.TestBuilderContext.Current.ObjectBag["MyDisplayNamePrefix", "Category");

And then a custom attribute on the test like (pseudo-code):

public class CustomDisplayNamePrefixAttribute : Attribute, ITestRegisteredEventReceiver
{
    OnRegistered(TestContext context)
    {
        context.SetDisplayName(context.ObjectBag["MyDisplayNamePrefix"] + ": " + context.GetDisplayName())
    }
}

[TheRumle]

Not only is this easy to implement, but it works like a charm. After looking into the lifetime a bit more (it did take me a good readthrough GH comments/questions and not the docs :( ) this works like a charm

[thomhurst]

If there's bits in the docs that are missing but you think would be useful, I wouldn't mind a PR 😄