This is a piece of code that I am using in RDB, at some point, it threw a null reference exception:

I am ashamed to admit that I started doing some really deep debugging to understand the bug (this happen only under very strange circumstances).

When I figured out what it was, I was deeply ashamed, this is easy.

Yesterday I posted about doing scenario testing with Raven, and I showed the concept of what i am doing. This time, I wanted to show what I am actually talking about, and how this is implemented. Here are the current scenarios for Raven.

Each scenario is looks something like this (showing PutAndGetDocument here):

And the second request:

The scenarios are being picked up using:

public class AllScenariosWithoutExplicitScenario
{
    [Theory]
    [PropertyData("ScenariosWithoutExplicitScenario")]
    public void Execute(string file)

        new Scenario(Path.Combine(ScenariosPath, file+".saz")).Execute();
    }

    public static string ScenariosPath
    {
        get
        {
            return Directory.Exists(@"..\..\bin") // running in VS
                       ? @"..\..\Scenarios" : @"..\Raven.Scenarios\Scenarios";
        }
    }

    public static IEnumerable<object[]> ScenariosWithoutExplicitScenario
    {
        get
        {
            foreach (var file in Directory.GetFiles(ScenariosPath,"*.saz"))
            {
                if (typeof(Scenario).Assembly.GetType("Raven.Scenarios." +
                          Path.GetFileNameWithoutExtension(file) +"Scenario") != null)
                    continue;
                yield return new object[] {Path.GetFileNameWithoutExtension(file)};
            };
        }
    }
}

There are two reasons why I am ignoring explicit scenarios. Adding a class for a specific scenario allows me to run the scenario in the debugger, and also allow me to selectively skip certain scenarios if I need to.

Scenario.Execute is fairly involved, it parse the Fiddler’s saz file, build appropriate request and compare to the expect response, it is also smart enough to handle changing things like ETags and pass them along.

The end result is that I can very easily add new scenarios as I get new features to that requires tests.