The MOST critical concept for managing the building and testing of code in DevOps is:

Continuous integration (CI) is the most critical concept for managing the building and testing of code in DevOps. CI is the practice of merging all developers’ working copies of code to a shared mainline several times a day. This enables early detection and resolution of bugs, conflicts, and errors, as well as faster and more frequent feedback loops. CI also facilitates the automation of building, testing, and deploying code, which improves the quality, reliability, and security of the software delivery process. CI is a prerequisite for continuous delivery (CD) and continuous deployment (CD), which are the next stages of DevOps maturity that aim to deliver software to customers faster and more frequently. References:

ISACA, Certificate of Cloud Auditing Knowledge (CCAK) Study Guide, 2021, p. 114-115

Cloud Security Alliance (CSA), Cloud Controls Matrix (CCM) v4.0, 2021, DCS-01: Datacenter Security - Build and Test

What is Continuous Integration?

Continuous Integration vs Continuous Delivery vs Continuous Deployment