After Sorbet, Ruby team started to develop homebrew type checking system. We’ll take a look on type checking tools in Ruby, review pros and cons of all of them. We are going to do some type-checking tasks and experiments and consider if type checking in Ruby is ready for production usage.

This talk focuses on a technique that enables developers and organizations to spend their developers' time more efficiently. The technique produces actionable call to actions to eliminate "wiggle room" between the behavior specified by tests and the behavior implemented in the code. It can be seen as the spiritual successor to traditional line coverage, that, while easy to measure, was not a meaningful metric to base actionable items from. The talk will demonstrate using the mutant mutation testing tool on a life subject, and will feature a high degree of audience interaction.