How do you test pre-/post-conditions and invariants?

[Magnus Lie Hetland]

Or, more generally, how do you test asserts (which is what I'm using in 
my preconditions etc.)?

As far as I can see, collectException() won't collect errors, which is 
what assert() throws -- so what's the standard way of writing unit 
tests for preconditions that use assert? (I.e., test that they will, in 
fact, throw when you break them.)

--
Magnus Lie Hetland
http://hetland.org