Which testing level involves testing individual components?

Component (Unit) Testing is the level of testing that focuses specifically on verifying the functionality of individual components or units of a software application. These components can be classes, methods, or functions, and the goal of this testing is to validate that each one works correctly in isolation from the rest of the application.

At this stage, testers examine the logic and the behavior of each unit to ensure that they produce the expected outcomes when subjected to predefined inputs. Testing at this level often involves writing unit tests that automate the verification process, enabling continuous integration and swift detection of issues. The early identification of defects at the component level can significantly lead to improved software quality and ease future integration with other components.

This approach allows developers to focus on the correctness of each part before they are assembled into larger systems, thereby simplifying debugging and reducing the overall complexity of fixing errors in later stages of development.