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'.
(..) of the films he saw or who played in them. - That's right. - And no one saw him at the theatre. And the woman across the street-if her testimony don't prove it, nothing does. - That's right. She actually saw the killing. - Fellas, please. Let's go in order. Just a minute. Here's a woman... (..)1957 12 Angry Men
(..) complex case, murder in the first degree. Premeditated murder is the most serious charge tried in our criminal courts. You've listened to the testimony, had the law interpreted as it applies in this case. It's now your duty to sit down and try and separate the facts from the fancy. One man is dead. (..)1957 12 Angry Men