What does "test first development" mean?

"Test first development" refers to the practice where tests are designed and often written before code is developed to implement the features being tested. This approach is fundamental to Test-Driven Development (TDD), where the cycle involves writing a test for a new functionality, ensuring that the test fails initially since the implementation doesn't exist yet, and then developing the code to pass that test. This ensures a clear specification of what the code should achieve and promotes better design decisions while preventing unnecessary code from being created. By focusing on tests first, developers clarify their intentions and improve the maintainability and reliability of the software.

In the context of this question, "designing tests before satisfying them" encapsulates the essence of creating a test before the code, which guides the development process. This ensures testing is proactive rather than reactive, emphasizing quality from the onset of the development cycle.