You have API, integration, and UI tests. Tell me more.

API tests verify the operation of server interfaces, usually through HTTP requests. They focus on the correctness of responses, statuses, data structures, and business logic without UI.

Integration tests check the interaction between multiple system components, for example, between a database and a service, or between multiple services. The goal is to ensure that components work correctly together.

UI tests (user interface tests) verify the application's operation from the user's perspective: clicks, data entry, element display. They are usually implemented using automation tools (Selenium, Cypress).

Example:

• API test: send a POST request to create a user and check the response.
• Integration test: verify that after creating a user, data is correctly saved in the database.
• UI test: open the registration page, fill out the form, and verify that the user is successfully registered.

This approach provides coverage of different application levels and helps identify errors early.