Tests are a good baseline for defining the behavior of a program,
but for complicated programs, are tests enough?
[Scientist](https://github.com/trello/scientist) is a Node.js library
for creating and running experiments between old and new pieces of code.
Scientist makes it easy to refactor critical code paths with confidence.
It safely exposes refactorings to actual production interactions and measures
potential mismatches. Part experience report, refactoring discussion,
and workshop, this talk makes the case for changing software safely and will also explore safe refactoring techniques
at companies like Trello and GitHub.