Update proxy scheduler test to account for race

Running with the race detector may cause some parts
of the code to run slower causing a race in the scheduler
ordering.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

registry/proxy/scheduler/scheduler_test.go

@@ -89,25 +89,28 @@ func TestRestoreOld(t *testing.T) {
 		ref2.String(): true,
 	}
 
+	var wg sync.WaitGroup
+	wg.Add(len(remainingRepos))
 	var mu sync.Mutex
 	deleteFunc := func(r reference.Reference) error {
+		mu.Lock()
+		defer mu.Unlock()
 		if r.String() == ref1.String() && len(remainingRepos) == 2 {
-			t.Errorf("ref1 should be removed first")
+			t.Errorf("ref1 should not be removed first")
 		}
 		_, ok := remainingRepos[r.String()]
 		if !ok {
 			t.Fatalf("Trying to remove nonexistent repo: %s", r)
 		}
-		mu.Lock()
 		delete(remainingRepos, r.String())
-		mu.Unlock()
+		wg.Done()
 		return nil
 	}
 
 	timeUnit := time.Millisecond
 	serialized, err := json.Marshal(&map[string]schedulerEntry{
 		ref1.String(): {
-			Expiry:    time.Now().Add(1 * timeUnit),
+			Expiry:    time.Now().Add(10 * timeUnit),
 			Key:       ref1.String(),
 			EntryType: 0,
 		},
@@ -129,13 +132,14 @@ func TestRestoreOld(t *testing.T) {
 		t.Fatal("Unable to write serialized data to fs")
 	}
 	s := New(context.Background(), fs, "/ttl")
-	s.onBlobExpire = deleteFunc
+	s.OnBlobExpire(deleteFunc)
 	err = s.Start()
 	if err != nil {
 		t.Fatalf("Error starting ttlExpirationScheduler: %s", err)
 	}
+	defer s.Stop()
 
-	<-time.After(50 * timeUnit)
+	wg.Wait()
 	mu.Lock()
 	defer mu.Unlock()
 	if len(remainingRepos) != 0 {