End-to-End (E2E) tests are checks that make sure the whole system works from start to finish, just like a real user would use it.

How it works

Instead of testing only small parts, E2E tests follow a complete flow. For example: open the website, log in, add an item to the cart, buy it, and get a receipt. The test acts like a user clicking through steps. If any piece fails along the way, the whole journey fails.

Analogy

It's like testing a train ride. You don't just check the engine or the ticket machine separately. You buy a ticket, board the train, travel, and get off at your stop. If the whole trip works smoothly, the system is fine.