Question

I have a Sinatra app that runs inside of EventMachine. Currently, I am taking a post request of JSON data, deferring storage, and returning a 200 OK status code. The deferred task simply pushes the data to a queue and increments a stats counter. The code is similar to:

class App < Sinatra::Base
  ...

  post '/' do
    json = request.body.read

    operation = lambda do
      push_to_queue(json)
      incr_incoming_stats
    end
    callback = lambda {}

    EM.defer(operation, callback)
  end

  ...
end

My question is, how do I test this functionality. If I use Rack::Test::Methods, then I have to put in something like sleep 1 to make sure the deferred task has completed before checking the queue and stats such that my test may look like:

it 'should push data to queue with valid request' do
  post('/', @json)
  sleep 1
  @redis.llen("#{@opts[:redis_prefix]}-queue").should > 0
end

Any help is appreciated!

Answer 1

The solution was pretty simple and once I realized it, I felt kind of silly. I created a test-helper that contained the following:

module EM
  def self.defer(op, callback)
    callback.call(op.call)
  end
end

Then just include this into your test-files. This way the defer method will just run the operation and callback on the same thread.