Local development is always a challenge. First of all there are a lot of components that should be matched to reflect the actual production server and then there are also versions of PHP, MySQL, MariaDB that are needed to be matched. And on top of that all, some configurations are really hard to set up on local machine. And after all is set up and working there comes another project with different setup and versions. Not to mention if there is a need to revert briefly for some bug fix of a previous one.
Everyone who has ever submitted a patch has been working with DrupalCI. The project itself is maintained by the Drupal Association and has a very detailed roadmap on where they want to go with the project. During DrupalCon in Dublin, I have been talking with a lot of engineers from Drupal Association* in order to get a clear understanding on how DrupalCI has been build. It will take some time to learn the way of working of all the different components, so therefore I want to give you a small introduction on the architecture of DrupalCI.