How to learn to clearly understand where is unit testing, and where is functional?

Question

Software testing

Hello! I deal with testing and sometimes I can’t understand where to use the modular and where the functional. For example, checking what value a function returns is functional testing, making a POST or GET request and checking the result is already unit testing. With this, everything seems to be clear. But, for example, testing models in laravel is what kind of testing? And if there is a testing of relations of the model? In general, how do you learn to clearly understand where to use which testing? Help me please.

Answer 1

Functions are data manipulations: there is input data, and there is a return value.
Modules are already logic that depends not so much on data as on conditions / parameters.
When we conduct functional tests, then we check whether the function works correctly with the data. When we do unit testing, then we check whether the conditions / parameters are processed correctly (which data is not so important).

Answer 2

I think you're mixing flies and cutlets in a blender.
INTRODUCTORY
RATIONALE
ISTQB Glossary

1. component: A minimal software item that can be tested in isolation.
   
2. component testing ("unit testing" and "module testing" are synonyms of CT) : The testing of individual software components. [After IEEE 610]