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 medical evidence... that the crime Tom Robinson is charged with... ever took place. It has relied, instead... upon the testimony oftwo witnesses... whose evidence has not only been called into serious question... on cross-examination... but has been flatly contradicted (..)1962 To Kill a Mockingbird
(..) Did you, during all this running, run for a doctor? There wasn't no need to. I seen who done it. Now, Mr Ewell, you've heard the sheriff's testimony. Do you agree with his description of Mayella's injuries? I agree with everything Mr Tate said. Her eye was blacked. (..)1962 To Kill a Mockingbird