How to do tests on visual forms?

Question

Software testing

Question. I'm trying to get into the topic of development test coverage. With testing classes and procedures and functions that do not have a visual component, I sort of understood.
I can't figure out how to write tests for visual forms, especially testing those pieces of code that should work depending on user actions.

Answer 1

https://www.seleniumhq.org/projects/webdriver/ (and frameworks above it, like selenide, serenity and a dozen others)