Is it worth learning to write unit tests now, if so, is it worth using libraries for testing?

Question

PHP

Hello!
Is it worth learning to write unit tests now, if so, is it worth using libraries for testing?
I've been trying to figure out how to install PHPUnit for a whole day now. The thing is, I don't like black boxes (when I just follow the instructions and don't even have a clue what's going on "under the hood"). For me, PHPUnit is a black box. At the same time, I am completely new to PHP, but I want to write tests. I also don't like putting things off. Here decided to find any library for testing. Should I write tests using libraries? If not, why not? Should I use a library or is PHPUnit better? It is also worth noting that complex tests are not required to be written, but simply something like checking the values ​​returned by a particular function.
Thanks in advance!

Answer 1

Should I write tests using libraries?
PHPUnit or Codeception