Ketan's Musings

Fredrick recently asked on the swtbot newsgroup:

My goal is to be able to write some user acceptance tests (using Cucumber) to be able to tests some of my Eclipse plug-ins.

Cucumber is a BDD framework written in (J)ruby. It executes plain text files as functional tests. As a first step, the goal was to be able to print a simple ‘hello world’:

This required being able to bundle jruby with the necessary gems, the jruby jar is already OSGi-fied, so creating a manifest was not required.

First drop in the jruby-complete.jar that we just created inside the target eclipse’s plugins directory.

Then create an eclipse application with the following in it:

public class CucumberRunner implements IApplication {

    public Object start(IApplicationContext context) throws Exception {
        Bundle bundle = Platform.getBundle("org.jruby.jruby");

        URL jrubyHome = FileLocator.toFileURL(bundle.getEntry("/META-INF/jruby.home"));

        RubyInstanceConfig config = new RubyInstanceConfig();
        config.setJRubyHome(jrubyHome.toString());
        Ruby runtime = JavaEmbedUtils.initialize(new ArrayList(), config);
        RubyRuntimeAdapter evaler = JavaEmbedUtils.newRuntimeAdapter();
        evaler.eval(runtime, "p 'Hello, Eclipse World'");
        JavaEmbedUtils.terminate(runtime);

        return EXIT_OK;
    }

    public void stop() {
        // do nothing
    }
}

Hello, Eclipse World

Now all we needed was to be able to execute the cucumber executable instead of printing hello world

Import the cucumber plugin with a sample calculator to execute it:

Cucumber Output

Jruby-in a jar already bundles rspec and rake, so the goal was to find out where it gets packaged.

Download the jruby source zip, extract it and open the build.xml file, search for “rspec” (there’s two occurences) and you’ll find that it’s passed in as an argument to the gem installer, add in another line with “cucumber”:

<target name="install-gems">
  <property name="jruby.home" value="${basedir}"/>
  <java classname="org.jruby.Main" fork="true" maxmemory="${jruby.launch.memory}" failonerror="true">
    <classpath refid="build.classpath"/>
    <classpath path="${jruby.classes.dir}"/>
    <sysproperty key="jruby.home" value="${jruby.home}"/>
    <arg value="--command"/>
    <arg value="maybe_install_gems"/>
    <arg value="rspec"/>
    <arg value="rake"/>
    <arg value="cucumber"/> <!-- add cucumber -->
    <arg value="--env-shebang"/>
  </java>
</target>

Then run ant:

$ ant jar-complete

To verify that everything is fine:

$ java -jar lib/jruby-complete.jar -S gem list

*** LOCAL GEMS ***

builder (2.1.2)
cucumber (0.2.3)
diff-lcs (1.1.2)
polyglot (0.2.5)
rake (0.8.4)
rspec (1.2.2)
sources (0.0.1)
term-ansicolor (1.0.3)
treetop (1.2.5)

Great we’ve now managed to package jruby-in-a-jar with some additional gems. Now to run cucumber on jruby in eclipse.

I just started my adventure with rails a few nights ago. Figured that Active Scaffold based controllers do something that is different from the default controllers generated by the scaffold generator.

For one all controller tests broke when I moved to active scaffold. Here’s a blog post that talks about testing active scaffold based controllers.

Read more about using JRuby or Groovy to write eclipse plugins here: http://dev.eclipse.org/blogs/wayne/2007/07/26/making-eclipse-plug-ins-using-jruby-or-groovy/

Sidu has written a good post on why you ought to be attending the ThoughtWorks Master Class Series 2007.

Registrations for the Bangalore event have already come to a close down. We’re already sending invites for the Pune event. There’s still some invites left for the Pune event, and you can just about make it if you register quick.