The testing package provides a timeout flag, "if positive, sets an aggregate time limit for all tests", which defaults to zero (no timeout).

In https://go-review.googlesource.com/#/c/8998/ I wanted a timeout for an individual TestFooBar test. It wasn't too hard to implement myself, but it should be part of the standard testing library.