Unit vs regression testing

Question

Software testing

Suppose the following situation: a certain library is developed using TDD, and for each method from the library there is a test that determines its behavior. Can the concept of regression tests arise in such a situation?

Answer 1

You are confusing warm with soft. Unit tests fall into the category of the size of the object under test—unit tests test a single module (class or method), integration tests test the interfacing of multiple modules, and system tests test the entire system from top to bottom.
Regression tests are tests that help detect (and prevent) re-breaking of functionality. Those. any tests (unit, etc.) not removed after the initial testing of the functionality, but left in the test suite and (most importantly!) run quite often will be regression if they help prevent breaking the existing functionality.

Answer 2

It seems to me that it can, but this is only when it will be necessary to refactor the library, and then check whether the tests that were previously written are executed.