Test-Driven Development
Definition
Test-Driven Development (TDD) is a software development practice that involves writing tests before writing the code itself.
This methodology follows a cyclical approach. First, a developer writes an automated test case that defines a desired improvement or new function. This test will initially fail because the corresponding code has not yet been written. Next, the developer writes just enough code to make the test pass. Finally, the code is refactored to improve its structure and efficiency while ensuring that all existing tests continue to pass. This red-green-refactor cycle ensures that code is built with a focus on its intended behavior and maintainability.
An example of its use would be writing a test that asserts a function returns "hello" when given an empty string, then implementing the function to satisfy that assertion.
This approach is prevalent in agile software development, particularly in projects emphasizing code quality, rapid iteration, and robust error handling.