Investigate how to create specific tests for Spring controllers

[EgorkaKulikov]

Description

In accordance with some articles, unit tests for the controllers may be created a little bit different than for services
https://salithachathuranga94.medium.com/unit-and-integration-testing-in-spring-boot-micro-service-901fc53b0dff

We should investigate:

• how it works in details (e.g. the difference between @Mock and @MockBean)
• is it really useful
• is it possible to implement smth like this in UtBot

[IlyaMuravjov]

I am not sure if we are capable of generating tests shown in linked article as unit tests, since although they use a lot of mocks, they still do seem to require starting an application.