Fix timer leak in wait.Poll

pkg/util/wait/wait.go

@@ -132,7 +132,12 @@ func poller(interval, timeout time.Duration) WaitFunc {
 			for {
 				select {
 				case <-tick.C:
-					ch <- struct{}{}
+					// If the consumer isn't ready for this signal drop it and
+					// check the other channels.
+					select {
+					case ch <- struct{}{}:
+					default:
+					}
 				case <-after:
 					return
 				case <-done:

pkg/util/wait/wait_test.go

@@ -257,3 +257,18 @@ func TestWaitFor(t *testing.T) {
 		}
 	}
 }
+
+func TestWaitForWithDelay(t *testing.T) {
+	done := make(chan struct{})
+	defer close(done)
+	WaitFor(poller(time.Millisecond, util.ForeverTestTimeout), func() (bool, error) {
+		time.Sleep(10 * time.Millisecond)
+		return true, nil
+	}, done)
+	// If polling goroutine doesn't see the done signal it will leak timers.
+	select {
+	case done <- struct{}{}:
+	case <-time.After(util.ForeverTestTimeout):
+		t.Errorf("expected an ack of the done signal.")
+	}
+}