The popularity of diet fads is a 'testimony to' the fact that people want a quick fix for their health and weight problems.
It is 'testimony to' her courage and persistence that she worked for so long in the face of such adversity.
There were contradictions in her 'testimony'.
(..) Yeah. And they were the size and shape of whom? They were the size and shape of most any Baird student, sir. I am left with no real witness. Mr. Willis' testimony is not only vague, it is unsubstantiated. The substance I was Iooking for, Mr. Simms, was to come from you. I'm sorry. (..)1992 Scent of a Woman