Key features. (1) A connection to a version control repository. (2) An automated build script, run with every change to the version control repository. (3) Some sort of feedback mechanism (eg, e-mail). (4) A process for integrating the source code changes (either manual or CI server).
Compile. Although you are not generating binaries using dynamic languages (eg, Python, PHP, Ruby), many provide the capability to perform strict checking.
Prepare database. We treat the database source code—Data Definition Language (DDL) scripts, Data Manipulation Language (DML) scripts, stored procedure definitions, partitioning, and so on—in the same manner as any other source code in the system. This includes scripts to drop and create tables and the database, apply procedures and triggers, and insert test data.
Test. Without automated unit, component, system, load and performance, security, etc. tests, it is difficult for developers or other project stakeholders to have confidence in software changes.
Inspect. Automated code inspections (eg, static and dynamic analysis) can be used to enhance the quality of the software by enforcing rules. You can use your CI system to run these rules automatically against a code base. Using a report like this can enable continuous monitoring of coding standards and quality metrics.
Deploy. Generate bundled software artifacts with latest code changes and publish to test. CI can automatically deploy or install files to the appropriate environment, and may automatically roll back all changes applied in the deployment.
Execute the same automated build, with slightly different parameters, in each (eg, build, test, deploy) environment.
Tools periodically generate class diagrams and other information, all based on the committed source code in your version control repository.
A critical feature to good CI systems is speed. The essence of a CI system is to provide timely feedback to developers and project stakeholders. It’s easy to load so much into a CI system—for the sake of completeness—that it takes an unreasonable amount of time to finish a cycle. As such, a balance must be struck between the breadth and depth of a CI process against the need to provide rapid results. This is especially important when using continuous testing.
Questions
Are you using a version control repository (or SCM tool)?
Is your project’s build process automated and repeatable? Does it occur entirely without intervention?
Are you writing and running automated tests?
Is the execution of your tests a part of your build process?
How do you enforce coding and design standards?
Which of your feedback mechanisms are automated?
Are you using a separate integration machine to build software?
[Duvall et al. 2007, "Getting Started"]
