Otaku, Cedric's weblog

TestNG in Ruby

We're going global with this baby...

A discussion recently started on the comp.lang.ruby mailing-list about the possibility to port TestNG to Ruby.

While Ruby doesn't support annotations natively, it's actually quite easy to simulate and both Aslak and a participant of this thread have posted a technique to add annotations to Ruby.  For example:

config :after_test => true
def teardown
  puts "Test2#teardown called"
end

test :groups => ['one']
def test_method1
  puts "Test2#test_method1 called"
end

This trick relies on the fact that it's possible to add definitions to Class in Ruby.  The annotations config and test above are actually real methods that update fields added to the Class class.  When one of these methods is encountered in a Class definition, it is parsed and then silently discarded so it never actually gets added to the Class definition.  This is made possible by overriding the method_added method of the Class class, where you can control what to do whenever a new method definition is found by the parser.

You can find the full listing for an example implementation of this technique in this message from Ryan Leavengood.

I also suggested to replace testng.xml with a Ruby file containing these definitions (the Ruby community is usually not very friendly to XML file, and I can certainly sympathize with this feeling).

I'm curious to see where all this will lead...