The major does not believe that the machines will work, but he comes every day because he feels they must be tested. What does this say about his character?

He does not care for theories.

He is a man of habit and discipline.

He is hopefully optimistic.

He does not believe in sacrifice.

This sentence says that he is a man of habit and discipline.

A man of habit is someone who does the same thing in the same way with regular tendency. Moreover, a man of discipline is a man that carries out a task because he knows that it is his duty to do it. This sentence implies that the major is a man of habit and discipline because even though he does not hope that the machines will work, he tests them every day because he feels that it is his duty.