I'm not sure how it worked prior to 2.0 or if it was possibly, but you can build locally in 2.0 ($ circleci build) which I think is just a thin wrapper around a

I'm not sure how it worked prior to 2.0 or if it was possibly, but you can build locally in 2.0 ($ circleci build) which I think is just a thin wrapper around a docker build + docker run + run unit tests (or whatever you want). That said, you don't have to use Docker and for a small project with no dependencies or no system level dependencies, I think it's overkill personally, so I'd just test outside of Docker or use the new base images from Circle. https://circleci.com/docs/2.0/local-jobs/ https://circleci.com/docs/2.0/local-jobs/