protected static T Scenario <T>(string description, Func <StoreOptions, MartenRegistry.DocumentMappingExpression <T> > configuration = null) where T : new()
{
var options = new StoreOptions();
var expression = configuration(options);
options.ApplyConfiguration();
var mapping = options.Storage.MappingFor(typeof(T)).As <DocumentMapping <T> >();
var scenario = new CodeGenScenario <T>(description, mapping, options);
_scenarios.Add(scenario);
return(scenario.Document);
}