Gradle which supports rspec :-)

build.gradle

apply plugin: 'java'
apply plugin: 'groovy'
apply plugin: 'eclipse'

import org.rubygems.repository.GemResolver;

buildscript {
	repositories {
		mavenCentral()
	}
	dependencies {
		classpath group: 'org.jruby', name: 'jruby-complete', version: '1.6.3'
	}
}

configurations { gem }

dependencies {
  gem name: "rspec", version: "2.6.0"
}

repositories {
  mavenCentral()
  add(new GemResolver(buildscript.configurations.classpath.asPath, file(".gems")));
}


task(spec, dependsOn: ["classes", "testClasses"], type: JavaExec) {
  configurations.gem.asPath
  main = 'org.jruby.Main'
  classpath = sourceSets.test.runtimeClasspath + buildscript.configurations.classpath
  args = ['-S', 'rspec', 'src/spec/ruby']
  println file(".gems").path
  environment['GEM_HOME'] = file(".gems").path
  environment['GEM_PATH'] = file(".gems").path
  environment['PATH'] = file(".gems/bin").path + ":" + environment['PATH']
}

stack_spec.rb

require 'java'
require 'rspec'

describe "a stack" do
  subject { java.util.Stack.new }

  it { should be_empty }
end

Q: Where does the import org.rubygems.repository.GemResolver reside?
Can't seem to resolve it.