Has anyone had any luck using Thoughtbot's Shoulda gem with MacRuby for testing?

I'm getting errors like this:

1) Error:

test: My factorial method should return 1 when passed 0.(TC_Test):

NoMethodError: undefined method `test: My factorial method should return 1 when passed 0.' for #<TC_Test:0x200240f60>

I'm fairly new to both Ruby and MacRuby. I'm not sure if the problem is due to MiniTest replacing Test::Unit in Ruby 1.9. Or, if it is a MacRuby issue.

Here's my simple test file that works in ruby 1.8:

require 'rubygems'
gem 'thoughtbot-shoulda'
require 'shoulda'
require 'test/unit'

def fact(x)
  return 1 if x == 0
  return (1..x).inject(:*)
end

class TC_Test < Test::Unit::TestCase
  context "My factorial method" do
   should "return 1 when passed 0" do
   assert_equal 1, fact(0)
   end
   should "return 1 when passed 1" do
   assert_equal 1, fact(1)
   end
   should "return 6 when passed 3" do
   assert_equal 6, fact(3)
   end
  end
end

I'll keep on digging, but if anyone has any insight, I'd appreciate it!

/\/\ike