Atdd

• Given: Preconditions and setup
• When: Actions and events
• Then: Expected outcomes

2. Requirements Bridging

Bridge requirements and implementation:

• Convert user stories to scenarios
• Map acceptance criteria to tests
• Create executable specifications

3. User Behavior Testing

Ensure tests reflect actual user behavior:

• User-centric test design
• Business-readable test names
• Stakeholder collaboration

Gherkin Syntax

Structure

Feature: [Feature Name]
  [Feature description]

  Scenario: [Scenario Name]
    Given [precondition]
    When [action]
    Then [expected outcome]
    And [additional assertion]

Keywords

Example Feature File

Feature: User Authentication

  As a user
  I want to log in to the system
  So that I can access my account

  Background:
    Given the application is running
    And the database is connected

  Scenario: Successful login with valid credentials
    Given the user is on the login page
    When they enter a valid email "[email protected]"
    And they enter a valid password "password123"
    And they click the login button
    Then they should be redirected to the dashboard
    And they should see a welcome message
    And a session token should be created

  Scenario: Failed login with invalid password
    Given the user is on the login page
    When they enter a valid email "[email protected]"
    And they enter an invalid password "wrongpassword"
    And they click the login button
    Then they should see an error message "Invalid credentials"
    And they should remain on the login page
    And no session token should be created

  Scenario: Failed login with unregistered email
    Given the user is on the login page
    When they enter an unregistered email "[email protected]"
    And they enter any password "password123"
    And they click the login button
    Then they should see an error message "Invalid credentials"
    And they should remain on the login page

  Scenario: Rate limiting after failed attempts
    Given the user has failed login 5 times
    When they attempt to login again
    Then they should see a message "Too many attempts"
    And they should wait 15 minutes before retrying

Scenario Outline (Data-Driven)

Scenario Outline: Login validation
  Given the user is on the login page
  When they enter email "<email>"
  And they enter password "<password>"
  And they click the login button
  Then they should see "<message>"

  Examples:
    | email              | password     | message              |
    | [email protected]  | validpass    | Welcome!             |
    | [email protected]  | wrongpass    | Invalid credentials  |
    | invalid@email      | anypass      | Invalid email format |
    |                    | anypass      | Email required       |
    | [email protected]  |              | Password required    |

Best Practices

Writing Good Scenarios

Scenario Organization

features/
├── authentication/
│   ├── login.feature
│   ├── logout.feature
│   └── password-reset.feature
├── user-management/
│   ├── registration.feature
│   └── profile.feature
└── shopping/
    ├── cart.feature
    └── checkout.feature

Step Definitions

TypeScript/Cucumber Example

// steps/authentication.steps.ts
import { Given, When, Then } from '@cucumber/cucumber';

Given('the user is on the login page', async function() {
  await this.page.goto('/login');
});

When('they enter a valid email {string}', async function(email: string) {
  await this.page.fill('#email', email);
});

When('they click the login button', async function() {
  await this.page.click('#login-button');
});

Then('they should be redirected to the dashboard', async function() {
  await expect(this.page).toHaveURL('/dashboard');
});

Then('they should see a welcome message', async function() {
  await expect(this.page.locator('.welcome')).toBeVisible();
});

ATDD Workflow

Step 1: Write Feature File

1. Discuss requirements with stakeholders
2. Write scenarios in Gherkin
3. Review with team
4. Get approval

Step 2: Implement Step Definitions

1. Create step definition file
2. Implement each step
3. Run tests (should fail - RED)

Step 3: Implement Feature

1. Write minimal code to pass tests
2. Run tests (should pass - GREEN)
3. Refactor if needed

Step 4: Verify

1. All scenarios pass
2. Coverage meets threshold
3. Feature is complete

Integration

Used by:

• luthien: For creating integration/E2E tests
• celebrimbor: For understanding acceptance criteria during implementation
• mandos: For translating requirements to tasks

Related Skills:

• tdd-workflow: For unit-level test-driven development
• writing-plans: For incorporating acceptance criteria into plans

Framework Support

Output Format

### 🧪 ATDD Test Suite: User Authentication

**Feature:** User Authentication
**Scenarios:** 4
**Status:** ✅ All Passing

**Coverage:**
| Scenario | Status | Duration |
|----------|--------|----------|
| Successful login | ✅ Pass | 1.2s |
| Failed login - invalid password | ✅ Pass | 0.8s |
| Failed login - unregistered email | ✅ Pass | 0.9s |
| Rate limiting | ✅ Pass | 2.1s |

**Total Duration:** 5.0s