gistfile1.rbx

#Throw this in spec helper
def block_should(matcher, &block)
  block.should matcher
end

def block_should_not(matcher, &block)
  block.should_not matcher
end

#Use it like this
block_should change(Thing, :count).by(-1) do
 @thing.destroy
end

#Which is just a little cleaner version of this
lambda do
  @thing.destroy
end.should change(Thing, :count).by(1)