Continuos Integration with docker

Git has made merging almost a non event. A common way to handle development is to have a separate branch per feature and merge that feature back to the development/master branches when the feature is done and all tests pass. For unit tests, there is already viable tooling that can help you auto-test feature branches before you merge them into develop or master.Travis-ci already offers this for Github projects, you should try it out if you haven’t already!

When it comes to integration tests there is a problem. When you have complex integration tests that need a running environment, it can become hard to manage all these branches and environments. You could spin up VMs for each feature branch that you create or try to share one environment for all feature branches. Or the worst alternative: you can leave integration tests for the integration branch. The problem with the last option is that it breaks the principle of “do no harm”: you want to merge when you know it won’t break things and now you have a branch that’s meant to break? Sounds like bad design to me.