Test-driven development guides — write tests first, ship fewer bugs, and design better software.
Testing
ATDD (Acceptance Test-Driven Development) starts each feature with a failing acceptance test written in collaboration between developers, testers, and product owners. Unlike TDD (which is a solo technical practice) and BDD (which focuses on communication and specification language), ATDD is specifically about driving development from acceptance criteria. The cycle
Testing
TDD, BDD, and ATDD are all test-first development approaches, but they differ in scope, audience, and tooling. Understanding these differences helps you choose the right approach for each situation — and many teams use all three together. TDD: Test-Driven Development TDD is a developer practice. You write unit tests
Testing
Test-driven development in React is more challenging than server-side TDD, but it's absolutely practical. The key is knowing which layer you're testing: component behavior, custom hooks, or integration between components. TDD Setup for React Modern React TDD uses React Testing Library (RTL), which tests
Testing
TDD promises better design, faster feedback, and confident refactoring. Many teams try it and find the opposite: slow development, brittle tests, and refactoring that breaks dozens of tests at once. Usually the problem isn't TDD itself — it's specific anti-patterns that undermine the practice. Anti-Pattern
Testing
Test-driven development (TDD) is a software development practice where you write tests before writing code. It sounds backwards at first — how can you test something that doesn't exist yet? But once you experience the feedback loop, it's hard to go back. TDD changes how you
Testing
Backend TDD has a straightforward feedback loop: write a test for an endpoint or function, watch it fail, implement the minimum code to pass it. But the specifics matter — how you structure tests, what you mock, and where you draw boundaries between unit and integration tests. The Backend TDD Stack
Testing
Testing React components has a reputation for being awkward. Shallow rendering, mock components, snapshot tests that break on every change — these patterns produce test suites that slow teams down rather than help them. React Testing Library changed this by enforcing a simple rule: test components the way users use them,
Testing
Test-Driven Development has a reputation for being a discipline that sounds great in theory but falls apart under deadline pressure. That reputation is wrong, and the reason is usually a misunderstanding of what TDD actually is. TDD is not "write all your tests before you write any code.
Testing
TDD and BDD are often mentioned in the same breath, sometimes used interchangeably, and frequently confused with each other. Both are test-first development disciplines. Both produce better software than writing tests after the fact. But they operate at different levels, involve different audiences, and solve different problems. Using the
Testing
Python and pytest are a natural fit for TDD. pytest has minimal ceremony, excellent error messages, and a parametrize decorator that makes covering edge cases straightforward. This tutorial builds an order pricing engine from scratch using strict red-green-refactor discipline. No implementation code gets written until a test demands
Testing
The best way to learn TDD is to do it, not read about it. This tutorial walks through a complete TDD session in JavaScript using Jest. We will build a password validator from scratch — no implementation code until the tests demand it. By the end, you will have a fully
Testing
TDD is easy to practice on a greenfield project. You start from nothing, write the test, write the code, and the cycle works exactly as described in the textbooks. Legacy code is different. The code already exists. It was written without tests. It has dependencies that are hard to isolate,