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This guard extention allows you to run all of your specs on JRuby without the initial start up cost. It loads all of your application files in advance, and reloads any that change. That way, when you run RSpec, the JVM is already running, and your files have already been required.

Most of the config options available to guard-rspec work with this extension too.

How to Use On-Demand mode

Just add this to your guard file:

interactor :simple
guard 'jruby-rspec', :spec_paths => ["spec"]

Then run guard like this (probably with Bundler):

$ bundle exec guard
Using polling (Please help us to support your system better than that).
The signal USR1 is in use by the JVM and will not work correctly on this platform
Guard could not detect any of the supported notification libraries.
Guard is now watching at '~/myapp'
Guard::JRuby::RSpec is running, with RSpec!

Finished in 0.735 seconds
7 examples, 0 failures

The first time guard starts up, it will run all of your specs in order to bootstrap the runtime. This first run will be as slow as any other run on JRuby.

Once you change some files, and press return at the guard prompt to rerun your specs. You'll notice it's a lot faster than running rspec from the command line.

How to Use Autorun mode

Add something like this to your guard file (alternatives are in the template file):

interactor :simple
guard 'jruby-rspec' do
  watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }
  watch('spec/spec_helper.rb')  { "spec" }

Proceed as in on-demand mode.

Code Reloading

Since JRuby cannot fork, guard-jruby-rspec reloads code with load on each changed path, which can potentially cause weird side side effects or errors.

Rails 3.2+ projects also use the Rails reloader to unload classes on each run.

Loading classes more than once does not work if the class definition is not idempotent. When using this gem on a non Rails 3.2+ project, you may want to unload these classes manually if you get new errors on the 2nd run:

Pass in custom reloaders as an option:

unload_my_class     = lambda { |changed_paths| Object.send :remove_const, 'MyClass' }
reload_factory_girl = lambda { |changed_paths| FactoryGirl.reload } # Already included by default when FactoryGirl is loaded
guard 'jruby-rspec', :custom_reloaders => [unload_my_class, reload_factory_girl] do

Using CLI Options

The format that guard-jruby-rspec expects CLI options to be in is a little different than what guard-rspec exepcts. Here is an example:

interactor :simple
guard "jruby-rspec", :cli => ["-c", "-t~slow"]

The CLI options should be an Array containing a number of strings. Each string should be a flag and an option value with no space between the flag and the value.


  • Autorun specs like guard-rspec (want to integrate with guard-rspec so as to not duplicate all of it's logic).

  • Allow for extra rspec options

  • Fix the way guard uses stdin so its not flaky on JRuby

  • Work out the kinks in gj-rspec script so that specs can be run in main terminal.

Thank You

Thank you to the authors of guard-rspec. I'm piggybacking off of the hard work done by Thibaud Guillaume-Gentil and others!




RSpec on JRuby without the startup cost.



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