Commented Issue: Extend attribute assertions with property checks [12186]

See http://fluentassertions.codeplex.com/discussions/279305 and discussion on http://stackoverflow.com/questions/10752485/how-do-i-test-a-controller-to-ensure-that-the-authorize-filter-is-applied-to-it
Comments: I can't find a better syntax than what is currently implemented. And since these Type assertions will always be a bit technical, I think it is alright that you must specify the attribute property assertions by passing in a predicate.