feat: add WorkerTaskQueue#WaitForNoActiveTasks() for tests (#284)

* feat: add WorkerTaskQueue#WaitForNoActiveTasks() for tests

* fixup! feat: add WorkerTaskQueue#WaitForNoActiveTasks() for tests

taskqueue/taskqueue.go

@@ -2,6 +2,7 @@ package taskqueue
 
 import (
 	"context"
+	"sync/atomic"
 	"time"
 
 	"github.com/ipfs/go-peertaskqueue"
@@ -32,7 +33,9 @@ type WorkerTaskQueue struct {
 	cancelFn      func()
 	peerTaskQueue *peertaskqueue.PeerTaskQueue
 	workSignal    chan struct{}
+	noTaskSignal  chan struct{}
 	ticker        *time.Ticker
+	activeTasks   int32
 }
 
 // NewTaskQueue initializes a new queue
@@ -43,6 +46,7 @@ func NewTaskQueue(ctx context.Context) *WorkerTaskQueue {
 		cancelFn:      cancelFn,
 		peerTaskQueue: peertaskqueue.New(),
 		workSignal:    make(chan struct{}, 1),
+		noTaskSignal:  make(chan struct{}, 1),
 		ticker:        time.NewTicker(thawSpeed),
 	}
 }
@@ -88,6 +92,16 @@ func (tq *WorkerTaskQueue) Shutdown() {
 	tq.cancelFn()
 }
 
+func (tq *WorkerTaskQueue) WaitForNoActiveTasks() {
+	for atomic.LoadInt32(&tq.activeTasks) > 0 {
+		select {
+		case <-tq.ctx.Done():
+			return
+		case <-tq.noTaskSignal:
+		}
+	}
+}
+
 func (tq *WorkerTaskQueue) worker(executor Executor) {
 	targetWork := 1
 	for {
@@ -104,7 +118,14 @@ func (tq *WorkerTaskQueue) worker(executor Executor) {
 			}
 		}
 		for _, task := range tasks {
+			atomic.AddInt32(&tq.activeTasks, 1)
 			terminate := executor.ExecuteTask(tq.ctx, pid, task)
+			if atomic.AddInt32(&tq.activeTasks, -1) == 0 {
+				select {
+				case tq.noTaskSignal <- struct{}{}:
+				default:
+				}
+			}
 			if terminate {
 				return
 			}