Expresses the desired behavior of an application with test cases written in a simple form of natural language that is easy to understand by stakeholders—usually using the Given/When/Then format. Test cases are then automatically translated into executable tests.

Defines test cases at a low level, close to the implementation, using unit test frameworks.

Is primarily focused on non-functional testing techniques to ensure system reliability and performance.

Requires testing to be performed after development is completed to validate software functionality.