Clean shutdown of test apiserver

test/integration/controlplane/graceful_shutdown_test.go

@@ -70,7 +70,14 @@ func TestGracefulShutdown(t *testing.T) {
 	resp.Body.Close()
 
 	t.Logf("shutting down server")
-	tearDownOnce.Do(server.TearDownFn)
+	// We tear it down in the background to ensure that
+	// pending requests should work fine.
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		tearDownOnce.Do(server.TearDownFn)
+	}()
 
 	t.Logf("server should fail new requests")
 	if err := wait.Poll(time.Millisecond*100, wait.ForeverTestTimeout, func() (done bool, err error) {
@@ -100,6 +107,8 @@ func TestGracefulShutdown(t *testing.T) {
 		t.Fatal(err)
 	}
 	t.Logf("response: code %d, body: %s", respErr.resp.StatusCode, string(bs))
+
+	wg.Wait()
 }
 
 type responseErrorPair struct {