AutoMocking with StructureMap and Moq in BDD Cucumber Style

Base Test Class

public abstract class GivenA<T> where T : class
{
    private MoqAutoMocker<T> _autoMocker = new MoqAutoMocker<T>();

    protected T Target { get; private set; }

    [SetUp]
    public void Setup()
    {
        Given();
        When();
    }

    protected virtual void Given()
    {
        Target = _autoMocker.ClassUnderTest;
    }

    protected virtual void When()
    {}

    protected Mock<TT> GetMock<TT>() where TT : class
    {
        return Mock.Get(_autoMocker.Get<TT>());
    }

    protected void Verify<TT>(Expression<Action<TT>> verify) where TT : class
    {
        Mock.Get(_autoMocker.Get<TT>()).Verify(verify);
    }
}

public class ThenAttribute : TestAttribute
{}

Example Class Under Test

public class TaskRunner
{
    private IContextProvider _contextProvider;
    private ITask _task;

    public TaskRunner(IContextProvider contextProvider, ITask task)
    {
        _contextProvider = contextProvider;
        _task = task;
    }

    public void RunTaskWithContext()
    {
        var context = _contextProvider.GetContext();
        _task.Run(context);
    }
}

public interface IContextProvider 
{
    string GetContext();
}

public interface ITask 
{
    void Run(string context);
}

Example Unit Test

public class WhenIRunTaskWithContext : GivenA<TaskRunner>
{
    private string _context = "context code";

    public override Given()
    {
        base.Given();

        GetMock<IContextProvider>().Setup(m => m.GetContext()).Returns(_context);
    }

    public override void When()
    {
        Target.RunTaskWithContext();
    }

    [Then]
    public void TheContextIsFetched()
    {
        Verify<IContextProvider>(m => m.GetContext());
    }

    [Then]
    public void TheTaskIsRunWithContext()
    {
        Verify<ITask>(m => m.Run(_context));
    }
}