mocha developer - May 2008 - Block trap

Sorry if this is a duplicate post.

I''m trying to test this the couldn''t figure out if it was
possible to
trap the block that was being passed in:

def do_something(foo)
  Bar.transaction do
    foo.baz()
  end
end

I''d like my test to prove that foo.baz() is executed inside the  
block.  Normally I would have written something like this:

def test
   foo = mock("foo")	
   trapped_block = Bar.expects(:transaction).trap
   target.do_something(foo)

   foo.expects(:baz)
   trapped_block.execute()
end