This talk will focus on what it takes to maintain a Ruby implementation and the process behind it. While there will be a strong focus on how Rubinius handles this, most of the topics also apply to other implementations such as JRuby and Opal. We'll also look into writing tests for Ruby, how this has been handled historically and why it's so important to have good tests.

One of the examples I'll be showcasing is how String#scrub, a new method in Ruby 2, was implemented in co-operation with Charles Nutter from JRuby and why this took quite a large amount of time (nearly a month). Another example will be Kernel#caller_locations, a method recently added to Rubinius which highlighted a potential bug in the implementation of MRI itself 1.