End-to-End Testing (E2E Testing)

End-to-End Testing (E2E Testing) is a comprehensive testing methodology that simulates a complete user journey through an application to validate that all integrated components, from the user interface to the database and external services, work together seamlessly. This ensures the entire system functions as expected from start to finish.

Example: For an e-commerce website, E2E Testing would involve a full user flow: a tester logs in to their account, searches for a product, adds it to the shopping cart, proceeds to checkout, makes a payment, and receives an order confirmation email. This single test verifies not only the individual functionalities but also the correct interaction between the user interface, product database, payment gateway, and email service.