What is Test assertions in Laravel, and what role does it play in a real application?

What is Test assertions in Laravel, and what role does it play in a real application? In Laravel, test assertions should be understood as part of a larger application architecture rather than as an isolated API call. Assertions verify that returned values, database state and HTTP responses match expectations. A strong understanding includes its purpose, the layer where it belongs, the data or request flow it affects, and the situations where another mechanism may be more appropriate. Practical context: Laravel provides testing support for unit and feature tests so teams can verify business rules and application behavior automatically. The specific focus here is test assertions: Assertions verify that returned values, database state and HTTP responses match expectations. This question is designed to test not only terminology, but also how the concept fits into Laravel's request, application, database, security, or deployment workflow.