RSpec and RBehave runs on JRuby

I'm not sure if this is well known or not, so I've been meaning to write a quick notice about it. The short story is this: JRuby can run RSpec and RBehave. Why is this important? Well, you can write code that tests Java code using RSpec and RBehave, meaning that it will be possible to get much more readable tests, even for code living in Java land.

Even if your organization won't accept writing an application in Ruby, it would probably be easier to get the testing done in Ruby. And writing tests in an effective language means that you will either write more production code, or more tests. Either of those are a quite good outcome.

A quick example of this in action. To run this example, you need JRuby 1.0 or later, and the rspec gem:

require 'java'

describe java.util.ArrayList, " when first created" do
before(:each) do
  @list = java.util.ArrayList.new
end

it "should be empty" do
  @list.should be_empty
end

it "should be able to add an element" do
  @list.add "content"
end

it "should raise exception when getting anything" do
  lambda{ @list.get 0 }.should raise_error(java.lang.IndexOutOfBoundsException)
end
end

In this code the examples are not that realistic, but you can see that the RSpec code looks the same for Java code, as it does for Ruby code. Even the raise_error exception matcher works. You can run this:

jruby -S spec -fs arraylist_spec.rb

The RBehave test suite also runs, which means you can stop using JBehave now... =)

This is a perfect example of the intersection where JRuby's approach can be very powerful, utilizing the existing Ruby libraries to benefit your Java programming.