Question

I’m new to Ruby, and I’ve been trying to learn Rake, RSpec, and Cucumber. I found some code that will help me test my Rake tasks, but I’m having trouble getting it to work. I was told here: http://blog.codahale.com/2007/12/20/rake-vs-rspec-fight/ to drop this:

def describe_rake_task(task_name, filename, &block)
  require "rake"

  describe "Rake task #{task_name}" do
    attr_reader :task

    before(:all) do
      @rake = Rake::Application.new
      Rake.application = @rake
      load filename
      @task = Rake::Task[task_name]
    end

    after(:all) do
      Rake.application = nil
    end

    def invoke!
      for action in task.instance_eval { @actions }
        instance_eval(&action)
      end
    end

    instance_eval(&block)
  end
end

into my spec_helper.rb file.

I’ve managed to take this code out and run it in my cucumber steps like this:

When /^I run the update_installers task$/ do
 @rake = Rake::Application.new
 Rake.application = @rake
 load "lib/tasks/rakefile.rb"
 @task = Rake::Task["update_installers"]

 for action in @task.instance_eval { @actions }
  instance_eval(&action)
 end

 instance_eval(&block)

 Rake.application = nil
end

but when I try to get things working in rspec, I get the following error.

ArgumentError in ‘Rake task
install_grapevine should install to
the mygrapevine directory’

wrong number of arguments (1 for 2)
/spec/spec_helper.rb: 21:in instance_eval'
/spec/spec_helper.rb: 21:inblock in invoke!’
/spec/spec_helper.rb: 20:in each'
/spec/spec_helper.rb: 20:ininvoke!’
/spec/tasks/rakefile_spec.rb:12:in `block (2 levels) in
‘

Unfortunately, I’ve got just under a week of ruby under by belt, so the metaprogramming stuff is over my head. Could anyone point me in the right direction?

Answer 1

This works for me: (Rails3/ Ruby 1.9.2)

When /^the system does it's automated tasks$/ do    
  require "rake"
  @rake = Rake::Application.new
  Rake.application = @rake
  Rake.application.rake_require "tasks/cron"
  Rake::Task.define_task(:environment)
  @rake['cron'].invoke   
end

Substitute your rake task name here and also note that your require may be “lib/tasks/cron” if you don’t have the lib folder in your load path.

I agree that you should only do minimal work in the Rake task and push the rest to models for ease of testing. That being said I think it’s important to ensure that the code is ACTUALLY run in my cron tasks during my integration tests so I think very mild testing of the rake tasks is justified.