RSpec::EventMachine

This library provides some extensions to RSpec that make testing EventMachine-based applications easier. It includes functionality for running asynchronous code in tests, and for stubbing out the EventMachine timer methods.

Installation

$ gem install rspec-eventmachine

Usage

The library includes two main modules: AsyncSteps facilities the writing of tests with async logic, and FakeClock stubs out timer methods.

`AsyncSteps`

To keep async tests clean, it helps to implement all the separate logical steps in them as separate functions. Using AsyncSteps, you write a module containing definitions of all your test steps, where each method takes a callback. You then mix this module into your tests, and you can use the methods without callbacks to write terse, flat tests.

require "rspec/em"

MathSteps = RSpec::EM.async_steps do
  def add(x, y, &callback)
    EM.add_timer 0.1 do
      @result = x + y
      callback.call
    end
  end

  def multiply(f, &callback)
    EM.add_timer 0.2 do
      @result = @result * f
      callback.call
    end
  end

  def check_result(n, &callback)
    @result.should == n
    callback.call
  end
end

describe "Math" do
  include MathSteps

  it "adds and multiplies" do
    add 3, 4
    multiply 5
    check_result 35
  end
end

Note that you must put all the logic in the async steps module. The method calls in your before, after and it blocks are really just adding the named methods and arguments to a queue, which AsyncSteps executes sequentially by calling each method when the previous one invokes its callback. AsyncSteps also makes sure that the reactor is running for the duration of each test, and catches and reports any errors or failures that happen during the test.

`FakeClock`

The FakeClock module lets you freeze time and move it forward by hand, to test code that uses the EventMachine add_timer and add_periodic_timer methods.

require "rspec/em"

describe "Math" do
  include RSpec::EM::FakeClock

  before { clock.stub }
  after { clock.reset }

  it "adds and multiplies" do
    value = 0
    EM.add_timer(1) { value += 3 }
    EM.add_timer(3) { value *= 2 }

    clock.tick(2)
    value.should == 3
    clock.tick(2)
    value.should == 6
  end
end

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.