Ruby on Rails

I've contributed to the Octobox app (https://github.com/octobox/octobox).  I've been using a weird system of using Docker.  Instead of using it the normal way, I create my own custom Docker image for each Rails project that I'm on.  When I log into my custom Docker container, I basically follow the same procedure that the people who rely on their host environments do.

I'm trying to learn the more conventional way of using Docker with docker-compose, but I'm having difficulty finding out how you're supposed to run the test suite.

I've followed the instructions at https://github.com/octobox/octobox/blob/master/docs/INSTALLATION.md#using-docker-and-docker-compose .  While I've been able to get the development environment working, I have not been able to figure out how I'm supposed to run the test suite with the docker-compose command.  Exactly what is the command for running the test suite?