Eventmachine talk - Jan 2008 - cat em_spec_helper_spec.rb

# I''m interested in what you all think of this. Some units/examples
(particularly those interested with timers in a more complex app)
require eventmachine to be running.
# My solution to date has been to completely extract the call to
eventmachine run to the outtermost call I can.
# Several areas are of interest to me in this regard:
#  * devs on win32 need a replacement for reactor_running? when on the
0.8.1 gem
#  * It''s easier to spin off a thread than to dig into rspec and
''fix''
the runtime orders of things
#  * The started thread is always sleeping to ruby(?)
#  * This also allows multiple calls to run:
#      - We have some integration suite tests which need to start up
several eventmachine apps inside each other.
#      - Whilst we have control of our code, a couple of complex
setups end up using say, an EM connection lib inside an
evented_mongrel. Here one must avoid run being called twice.
#      - It is possible to do all of the above in logic, but the anti-
pattern results in hard segfaults
#
#  * Is it time to make run not clobber itself (and the rest of the
process) when already running?
#      - Under what conditions is this specifically not desirable?
#
# I hope someone else might find this useful too.

#!/usr/bin/env ruby

require ''rubygems''
require ''spec''

require ''eventmachine''
require ''thread''
Thread.abort_on_exception = true

class <<EventMachine
   def reactor_running?
     @reactor_running
   end unless defined?(reactor_running?)

   alias run! run
   def start
     unless reactor_running?
       job = proc { run! }
       @start_run_thread = Thread.new &job
     end
     @reactor_running = true
     reactor_running?
   end

   def stop!
     stop
     @reactor_running = false
     raise ''EventMachine thread did not stop correctly!''
unless
@start_run_thread.join
   end

   def run &blk
     if start
       yield if block_given?
     else
       raise ''Failed to start EventMachine''
     end
   end
end

Spec::Runner.configure do |config|
   config.before(:all) {
     ::EventMachine::run
   }
   config.after(:all) {
     ::EventMachine::stop!
   }
end

describe ''eventmachine monkey patch helper'' do
   it ''should have started the reactor'' do
     ::EventMachine.should be_reactor_running
   end
end