Scientist is a Ruby library for refactoring critical paths. It allows you to compare the current and refactored behaviors of a large web app under load. The library provides a way to wrap code in use and try blocks, measure the durations of the behaviors, compare the results, and publish the information. You can also customize the comparison and cleaning of values, add context to experiments, enable or disable experiments based on conditions, and handle errors. Scientist is useful for carefully testing and monitoring changes in web apps.
https://github.com/github/scientist