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TDD (Test-Driven Development)

Direct answer

What is TDD (Test-Driven Development)?

Short definition

TDD is a development approach where you write tests before writing code, then write just enough code to make tests pass—a cycle called Red-Green-Refactor.

Why it matters
TDD catches bugs early, ensures tests actually test what matters, and creates a safety net that enables confident refactoring and long-term maintainability.

How teams use TDD (Test-Driven Development)

Use this term when you need to describe the practical role it plays in a software project.

Common use cases

  • Writing tests that define expected behavior first
  • Ensuring new features don't break existing functionality
  • Documenting expected behavior through tests
  • Enabling confident refactoring

Examples of TDD (Test-Driven Development)

These examples show the term in everyday product, platform, or operations work.

Real-world examples

  • Writing test for user registration before implementing it
  • PHPUnit tests verifying API endpoint responses
  • Browser tests confirming checkout flow works end-to-end

Related terms