So far we have been depending on the developer to ensure that the changes they push up to the GitHub remote repository do not cause regressions elsewhere in the application, by running Apex tests before making their commits. This is always a good practice!

However, this is not always a fully reliable means of determining the quality of the code, as the main code base will likely have moved on due to other developers also pushing their changes. When integrated together, they might cause tests or even code to fail to compile. Continuous Integration monitors changes to the Source Control repository and automatically starts its own build over the fully integrated source code base. Failures are reported back to the developers who last pushed code to the repository.

In this part of the chapter, we are going to explore this process using the popular Jenkins Continuous Integration server that uses the Ant script to perform the build step. Before we get into setting...