em-rspec is a very simple patch to RSpec 2 that sets up and tears down an EventMachine reactor loop, and runs each example within the context of the loop. It also will wrap each example in a Fiber so you are free to untangle nested callbacks.
gem install em-rspec
em-rspec extends RSpec in an unobtrusive way that requires no addtional code in your specs to test EM code. e.g.
describe 'em-rspec' do it 'executes specs within a reactor loop' do EM.reactor_running?.should be_true # This is true end end
How it works
As mentioned before, before the spec is run, a reactor loop is setup, and a callback to teardown the loop when your example finishes execution is created. This is an important point to consider because if you do any asynchronous i/o operations, your code will not be tested, because your code will likely have finished execution before the i/o operation is complete. It is an antipattern to actually hit the network in your tests and what you should do is mock out i/o calls to return immediately, e.g. http calls with webmock.
This is how your examples are run with em-rspec:
- Set up reactor loop
- Set callback to tear down reactor loop when spec is finished
- Wrap example in fiber
- Run before each block
- Run example
- Run after each block
- Tear down reactor loop
© 2011 Stevie Graham