test-driven-development

Test-driven development (TDD) is a software testing workflow where you write a failing test before implementing code. It improves code quality by ensuring features meet requirements, promoting minimal implementation, and enabling safe refactoring without breaking existing tests.

To start TDD, write a test for the expected behavior first. Follow the Red-Green-Refactor cycle: write a failing test, implement minimal code to pass it, then refactor while ensuring all tests still pass.

Test-driven development requires a test runner and a development environment to execute tests. No specific framework is mandated, so you can apply this workflow using whatever software testing tools your project already supports.

Use test-driven development during software development processes where verification and validation of code is critical. It is ideal when implementing features or fixing bugs that require strict confidence in code quality and behavior.

Test-driven development requires a failing test first to verify the test itself works and to define clear requirements. This ensures you write only the necessary minimal code to pass the test, avoiding over-engineering.

Enforcing test-driven development adds upfront overhead by requiring tests before implementation. It is less suited for exploratory prototyping where requirements are unclear and depends on having a fully configured test runner environment.