t.Fatalf("unexpected error: %v", err)
	}
	if err := ps.Subscribe(MaskAll, ch2, doneCh, nil); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	ps.Lock()
	defer ps.Unlock()

	if len(ps.subs) != 2 || ps.NumSubscribers(MaskAll) != 2 || ps.Subscribers() != 2 {
		t.Fatalf("expected 2 subscribers")
	}
}

func TestNumSubscribersMask(t *testing.T) {
	ps := New[Maskable, Mask](2)
	ch1 := make(chan Maskable, 1)

			if wg != nil {
				wg.Done()
			}
			// Clean up and de-register the subscriber
			ps.Lock()
			defer ps.Unlock()
			var remainTypes Mask
			for i, s := range ps.subs {
				if s == sub {
					ps.subs = append(ps.subs[:i], ps.subs[i+1:]...)
				} else {
					remainTypes.Merge(s.types)
				}
			}
			atomic.StoreUint64(&ps.types, uint64(remainTypes))
			atomic.AddInt32(&ps.numSubscribers, -1)
		}()