counter

type GoRoutineCounter ¶

type GoRoutineCounter interface {
	// Add adds the given delta to the count of active goroutines.
	// Call Add(1) before forking a goroutine, Add(-1) at the end of that goroutine.
	// Call Add(-1) just before waiting on something from another goroutine (e.g.,
	// just before a `select`).
	// Call Add(1) just before doing something that unblocks a goroutine that is
	// waiting on that something.
	Add(delta int)
}

GoRoutineCounter keeps track of the number of active goroutines working on/for something. This is a utility that makes such code more testable. The code uses this utility to report the number of active goroutines to the test code, so that the test code can advance a fake clock when and only when the code being tested has finished all the work that is ready to do at the present time.