Unit Testing vs Integration Testing vs End-to-End Testing

Wed, 14 Oct 2026 19:31:24 +0300

A customer applies a discount, pays for an order, and sees a confirmation page. The feature works on a developer’s laptop. Then the production release fails because the discount rounds differently in one case, the database rejects a field, or the checkout button waits for an element that never appears.

All three failures belong to the same feature. They do not belong to the same test.

That distinction is the heart of unit testing vs integration testing vs end-to-end testing. These test types are not competing ways to prove that software works. Each looks at a different boundary and answers a different question:

End-to-End-Testing on Compile My Mind

Unit Testing vs Integration Testing vs End-to-End Testing