What is "functional-testing"

Functional tests are those that seek to test the functionalities of your application, verifying the integration between the various parts that compose it. The idea is to simulate the interaction of a real user with the system, without worrying about the implementation details of the functionality. Here we have a higher level of abstraction than in unit tests, where we test code details. Normally functional tests are black box tests: You provide inputs, receive outputs, and verify that they are correct. How the system processed the inputs does not matter at this point.