Test every feature (Create unit tests and integration tests) #116
Description
We need to strengthen our test coverage by maintaining existing unit tests and adding new ones for the User and RetailCompany domains. This ensures reliability, prevents regressions, and validates new features (e.g., following companies, viewing products/events).
User Story
As a developer,
I want comprehensive unit tests for User and RetailCompany entities and services,
So that I can confidently refactor and extend functionality without breaking existing behavior.