Module 11: TDD & BDD
Duration: 2-3 hours | Difficulty: Intermediate
Test-Driven Development (TDD) and Behavior-Driven Development (BDD) are methodologies where tests are written before code. This leads to better-designed, more maintainable software.
What You'll Learn
- The Red-Green-Refactor cycle
- TDD in practice
- BDD with Given-When-Then
- Cucumber/Gherkin syntax
- SpecWeave's test-first approach
Module Lessons
| Lesson | Topic | Duration |
|---|---|---|
| 11.1 TDD Fundamentals | Red-Green-Refactor cycle | 45 min |
| 11.2 TDD in Practice | Complete TDD example | 45 min |
| 11.3 BDD Introduction | Behavior-Driven Development | 30 min |
| 11.4 Gherkin Syntax | Writing Given-When-Then scenarios | 30 min |
| 11.5 SpecWeave TDD | Test-first with SpecWeave | 30 min |
The TDD Cycle
- Red: Write a test that fails (code doesn't exist yet)
- Green: Write minimal code to make test pass
- Refactor: Improve code while keeping tests green
BDD Example
Feature: User Login
Scenario: Successful login with valid credentials
Given a registered user with email "user@example.com"
And the user's password is "SecurePass123"
When the user submits the login form
Then the user should be redirected to the dashboard
And a session token should be stored
Why TDD/BDD?
| Benefit | Description |
|---|---|
| Better Design | Tests force you to think about API before implementation |
| Complete Coverage | Every line has a test by definition |
| Living Docs | Tests show how code should be used |
| Fewer Bugs | Catch bugs before implementation |
| Refactoring Confidence | Tests ensure behavior doesn't change |
Prerequisites
Before starting:
- ✅ Completed Modules 07-10
- ✅ Comfortable writing tests
- ✅ Understanding of test pyramid
Let's Begin
Ready to write tests before code?