What is the difference between test-driven and behavior-driven development?

Question

Accepted Answer

**TDD** — write tests first. **BDD** — write behavior specs first.

**Test-Driven Development (TDD):**
- Write test before code.
- Red-Green-Refactor.
- Focus on unit tests.
- Developer-centric.

```
TDD Cycle:
1. Write failing test (Red)
2. Write minimal code (Green)
3. Refactor
(Repeat)
```

**Behavior-Driven Development (BDD):**
- Write behavior specs.
- Given/When/Then format.
- Focus on user behavior.
- Stakeholder-centric.

```
BDD Spec:
Given a logged-in user
When they add an item to cart
Then the cart total updates
(Behavior-focused)
```

**Key differences:**
- **TDD** — tests.
- **BDD** — behavior.
- **TDD** — developer.
- **BDD** — stakeholder.

Systems Analyst: What is the difference between test-driven and behavior-driven development?