Test changes before merging

That seems obvious, doesn’t it? Why would anyone do it the other way around? I don’t know, but it happens.

Let’s say you finished a feature in your project and you want to merge the feature branch into the master branch of your project’s git repository. The master branch is considered stable (i.e. it should always work) and is used by other developers as a basis for their own work as well as for releasing new versions.

You also have some sort of automated testing, i.e. Jenkins jobs running unit and integration tests.

The workflow when you merge your feature branch into the master and publish it with the aim that your testing system will kick-in and let you know that master is OK (or not) is flawed by design. After you publish your changes it’s already too late to test it. Anybody who pulls the master branch now will see the untested commits and will end up with a potentially broken source code. It’s not a big deal for a personal project involving two people. It’s a very, very big problem in a project developed by 50-100 people where most of them work like this.

Always run tests before you merge your feature branch into the master. Design your tests, build system and/or Jenkins jobs to support this workflow. It will make your life as a developer a lot easier:

• Your commits won’t break other people’s work
• If you find that your commits break something you can easily fix them or throw them away, without reverting anything in master
• You will have a more stable project and less frustrated colleagues