In simple words, continuous integration or CI is a software engineering practice, where each check-in made by a developer is verified by either of the following:
- Pull mechanism: executing an automated build at a scheduled time
- Push mechanism: executing an automated build when changes are saved in the repository
This step is followed by executing a unit test against the latest changes available in the source code repository. Continuous integration is a popular DevOps practice that requires developers to integrate code into code repositories such as Git and SVN multiple times a day to verify the integrity of the code.
Each check-in is then verified by an automated build, allowing teams to detect problems early.