How do you do "unit tests" in Unity?

I understand the concepts of "unit testing", and how important it is for software development.

But I never been able to see code by code, line by line, how it is written. Not even a screenshot, if I can recall.

When you are scripting, how do you do unit testing?

For instance, I want to know if entity attacking interaction works. So I would isolate 2 game units, A and B, have one of them attack the other, and check the Console to see what the outputs are. No need for animation, or particle effects.

Would it look like:

Code (csharp):

1.  
2. GameUnit b;
3. //...Some actions later.
4. GameUnit a = GetComponent<GameUnit>();
5. Debug.Log("Results: " + a.Attack(b));
6.  

Or something else? I would be happy to see some actual code examples, or a project package.