Guide on Test-First Development for PMI-ACP TDD

What is Test-First Development?
Test First Development(TFD) is an approach in software development whereby the tests are written before the actual code. It is a major element of Extreme Programming (XP) and is very closely related to Test-Driven Development(TDD).

Importance of Test-First Development
Test-first Development enhances the developer's understanding of the requirements and scope of the project, thereby reducing possible misunderstandings. It leads to more reliable, error-free code, and shortens the debugging process. Lastly, writing tests beforehand ensures that the final product is testable which is a crucial quality attribute of a system.

How Test-First Development Works
In TFD, a test is created that specifies and validates what the code will do. Initially, the test will fail as the code is not yet implemented. The developer then produces the minimum amount of code to pass that test, and subsequently refactors the new code to acceptable standards.

Answering Questions on Test-First Development in an Exam
The key aspect is to understand the principles of TFD: write test cases first, then write the code to pass the test, and finally refactor code. Grasp its importance, benefits, and how it improves code quality and maintainability.

Exam Tips:
1. Understand the main concept of writing tests first and coding later.
2. Recognize the importance and benefits of Test-First Development.
3. Understand how TFD works in a real-time project.
4. Emphasize the inter-relationship between TFD and XP.
5. Always reemphasize the cycle- write test, write code, refactor code.
6. Understand the point of writing the minimal code to make the test pass.