I want to know whether the "unit test" can test the display function of lcd?

I read the introduction of unit test and it seems that only some numbers and string types can be tested. Can “unit test” test such as lcd display function? I want to separate the formal code from the test code.

Please eloborate. Do you want the business logic to be able to do some internal logic, which eventually calls into some LCD library function, and a unit test should check whether the e.g. LCD’s print function was called with the correct arguments? Is that unit test supposed to be executed on the embedded device or on the PC / natively?