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A Rails app I'm working on performs some expensive operations that should be offloaded to another process, so I'm using this as an opportunity to try out BackgrounDRb. Because I'm doing BDD with RSpec, my first instinct, after installing and generating a worker, was to write a spec for my worker. However, Googling for the best way to do this turned up nothing, so I'm posting what I did. If you have a better way to do this, I'd love to hear it. If not, I hope this saves someone some time.

First, I created a new directory under my spec directory:

svn mkdir spec/workers

Then, I wrote the following in a file called collecting_worker_spec.rb in the newly-created workers directory (my worker is called CollectingWorker)

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require File.dirname(__FILE__) + '/../spec_helper'

describe CollectingWorker, "with feeds needing collection" do
  
  before(:each) do
    @worker = CollectingWorker.new
  end       
  
  it "should pull a single feed" do                        
    mock_collector = returning mock('collector') do |m|
      m.should_receive(:collect)
    end
    Collector.should_receive(:pop).and_return(mock_collector)
    @worker.do_work(true)
  end
end

For this spec to run correctly, though, I needed to add some code to my spec_helper.rb. This isn't pretty, but it is working for me:

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module BackgrounDRb
  module Worker
    class RailsBase 
      def self.register; end
    end
  end
end 

worker_path = File.dirname(__FILE__) + "/../lib/workers"
spec_files = Dir.entries(worker_path).select {|x| /\.rb\z/ =~ x}
spec_files -= [ File.basename(__FILE__) ]
spec_files.each do |path|
  require(File.join(worker_path, path))
end

All of the necessary RailsBase methods get mocked or stubbed in the spec itself. The class declaration is there so the necessary constants can be found when they're needed. There's probably a better place for that declaration, but the fact that so little code is needed for me to begin speccing my workers is a testament to the power of RSpec and its mocking facilities.