assert_yields

I got sick of writing longhand assertions around yields so I whipped up this little function:

  
def assert_yields(something_callable, arg)
   yielded = false
   something_callable.call(arg) do
     yielded = true
   end
   assert yielded
end

# Called like:
assert_yields(some_obj.method(:do_something), my_arg)

One could easily make it handle a variable number of arguments.