The model of a program is an analysis that describes its structure in limited detail.
Single point of control
Single point of control reflects the quality of being able to change a value in one place, and have all its dependencies be able to use the new value.
Traceability reflects the quality of being able to see clearly the connections between code and its underlying model.
White-box testing allows you to base your tests on your knowledge of what the program is supposed to do (that is, its internal model). You choose parameters of the tests to exercise paths in the code through to expected outputs.