test: IngressClass exclusion test races with admission cache

The admission cache may take longer to see both ingress classes
than it takes to create the ingress. We must loop until we see
the appropriate error, cleaning up after ourselves as we go.

Author: smarterclayton

test/e2e/network/ingressclass.go

@@ -19,10 +19,12 @@ package network
 import (
 	"context"
 	"strings"
+	"time"
 
 	networkingv1beta1 "k8s.io/api/networking/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	"k8s.io/apimachinery/pkg/util/wait"
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/kubernetes/test/e2e/framework"
 
@@ -73,14 +75,19 @@ var _ = SIGDescribe("IngressClass [Feature:Ingress]", func() {
 		framework.ExpectNoError(err)
 		defer deleteIngressClass(cs, ingressClass2.Name)
 
-		_, err = createBasicIngress(cs, f.Namespace.Name)
-		if err == nil {
-			framework.Failf("Expected error creating Ingress")
-		}
-
+		// the admission controller may take a few seconds to observe both ingress classes
 		expectedErr := "2 default IngressClasses were found, only 1 allowed"
-		if !strings.Contains(err.Error(), expectedErr) {
-			framework.Failf("Expected error to contain %s, got %s", expectedErr, err.Error())
+		var lastErr error
+		if err := wait.Poll(time.Second, time.Minute, func() (bool, error) {
+			defer cs.NetworkingV1beta1().Ingresses(f.Namespace.Name).Delete(context.TODO(), "ingress1", metav1.DeleteOptions{})
+			_, err := createBasicIngress(cs, f.Namespace.Name)
+			if err == nil {
+				return false, nil
+			}
+			lastErr = err
+			return strings.Contains(err.Error(), expectedErr), nil
+		}); err != nil {
+			framework.Failf("Expected error to contain %s, got %s", expectedErr, lastErr.Error())
 		}
 	})