Steve Holden writes:
"Fail" isn't a negative. As Guido said, it's a description of the test behavior under particular circumstances.
This is not true, however. "Fail" is a description of a potentailly very large class of behaviors. Knowing that the test failed does not tell you which of the failure behaviors occurred, only that the success behavior did not occur.
The analogy to the fact that True != not not 10 is telling, I think.