What is the difference between white box testing and black box testing? White box testing concerns checking outputs based on inputs; black box testing traces each path through the program modules. White box testing uses white boxes and black box testing uses black boxes. White box testing is a faster testing method than black box testing. White box testing traces each path through the program modules; black box testing concerns checking outputs based on inputs. When building a structure chart, what is an important question to ask yourself? How many modules does a structure chart generally need? What in my system - constitutes a module? Can I just add arrows to the DFD and call it good? Can I get away with just skipping this diagram?