This repository is an experiment about building monorepo projects using Travis CI.
Be sure to checkout my Circle CI monorepo demo if you are interested in other CI options.
It makes use of Travis matrix feature where in .travis.yml we define folders to different project locations in the repo.
What happens next is when Travis runs the build it creates a job for each defined project.
Then in each job it checks if the project has changes using git diff and runs tests if it does.