How would you test a login functionality? List test scenarios.

Functional Test Scenarios

1. Valid Credentials: Login with correct username and password
2. Invalid Username: Login with wrong username
3. Invalid Password: Login with wrong password
4. Empty Fields: Submit with empty username/password
5. Case Sensitivity: Test if username/password are case-sensitive
6. Special Characters: Test with special characters in credentials
7. SQL Injection: Test with SQL injection strings
8. Remember Me: Verify “Remember Me” functionality
9. Forgot Password: Test password reset flow
10. Account Lockout: Test after multiple failed attempts
11. Session Timeout: Verify session expires after inactivity
12. Logout: Verify logout clears session

UI/UX Test Scenarios

• Verify password is masked
• Check “Show Password” toggle works
• Verify error messages are clear and helpful
• Test tab navigation between fields
• Verify Enter key submits form
• Check responsive design on mobile

Security Test Scenarios

• Verify HTTPS is used
• Check password is not visible in network requests
• Test CAPTCHA after failed attempts
• Verify session token is secure
• Test against brute force attacks
• Check for XSS vulnerabilities

Performance Test Scenarios

• Test login response time
• Test with concurrent users
• Verify behavior under load

Compatibility Test Scenarios

• Test on different browsers (Chrome, Firefox, Safari, Edge)
• Test on different devices (Desktop, Mobile, Tablet)
• Test on different OS (Windows, Mac, Linux, iOS, Android)

Edge Cases

• Very long username/password
• Leading/trailing spaces in credentials
• Copy-paste credentials
• Browser back button after login
• Direct URL access to protected pages