I would think for unit testing it depends upon the scope of what you are looking to test in unit testing and the languages etc you are working with.
Generally at unit test level you are looking to:
*Recieve units of code that compile correctly.
*The units have no syntax or compile errors present.
*The input and output of the units are correct.
*The units conform to any corporate standards.
*The units assemble and function correctly together (strictly speaking intergration testing but can sit under unit test within some organisations).
*The units match their designed function as per the technical design.