I agree with the spirit of this post, but the idea of reading and understanding the code doesn't scale well. Perhaps a better way of expressing this is "trust,

I agree with the spirit of this post, but the idea of reading and understanding the code doesn't scale well. Perhaps a better way of expressing this is "trust, but verify". How trust is established varies depending on the size of the library and the reputation of the author(s). Verification obviously means rigorous testing.