Software Quality Assurance Practice Exam

The primary principle of Test-Driven Development (TDD) is to write tests before writing the corresponding code. This approach emphasizes the importance of defining the desired functionality and behavior of a software component through tests before any implementation begins. By establishing tests first, developers can ensure that their code only needs to satisfy the requirements laid out by those tests, leading to better design and more reliable software.

This methodology fosters a cycle of continuous improvement, where developers write a failing test that reflects a desired feature, then produce the minimum amount of code necessary to pass that test, and finally refactor the code while ensuring that all tests continue to pass. This not only helps in maintaining a clear focus on requirements but also supports finding defects early in the development cycle, thereby reducing long-term costs and improving software quality.

The other options do not align with the core principle of TDD. Writing tests for existing code, for instance, occurs after the code has already been implemented, which is contrary to the proactive nature of TDD. Running code reviews post-testing and automating software deployment are also practices valuable in software development but do not encapsulate the TDD approach of test initiation before coding.