Wait until all Pods are deleted in E2E

Signed-off-by: d-kuro <kurosawa7620@gmail.com>

e2e/backup_gcs_test.go

@@ -159,6 +159,21 @@ var _ = Context("backup-gcs", func() {
 	})
 
 	It("should delete namespace", func() {
-		kubectlSafe(nil, "delete", "ns", "backup-gcs")
+		kubectlSafe(nil, "delete", "-n", "backup-gcs", "mysqlclusters", "--all")
+
+		Eventually(func() error {
+			out, err := kubectl(nil, "get", "-n", "backup-gcs", "pod", "-o", "json")
+			if err != nil {
+				return err
+			}
+			pods := &corev1.PodList{}
+			if err := json.Unmarshal(out, pods); err != nil {
+				return err
+			}
+			if len(pods.Items) > 0 {
+				return errors.New("wait until all Pods are deleted")
+			}
+			return nil
+		}).Should(Succeed())
 	})
 })