Add e2e to check 0 size cluster

Author: frederiko

config/manager/kustomization.yaml

@@ -4,5 +4,5 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 images:
 - name: controller
-  newName: controller
-  newTag: latest
+  newName: etcd-operator
+  newTag: v0.1

test/e2e/e2e_test.go

@@ -26,10 +26,66 @@ import (
 	"sigs.k8s.io/e2e-framework/pkg/envconf"
 	"sigs.k8s.io/e2e-framework/pkg/features"
 
+	ecv1alpha1 "go.etcd.io/etcd-operator/api/v1alpha1"
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
+// An Etcd cluster with zero member should not create its StatefulSet counterpart
+func TestZeroMemberCluster(t *testing.T) {
+	feature := features.New("zero-member-cluster")
+	etcdClusterName := "etcd-cluster-zero"
+	size := 0
+
+	etcdClusterSpec := &ecv1alpha1.EtcdCluster{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "operator.etcd.io/v1alpha1",
+			Kind:       "EtcdCluster",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      etcdClusterName,
+			Namespace: namespace,
+		},
+		Spec: ecv1alpha1.EtcdClusterSpec{
+			Size:    size,
+			Version: "v3.5.18",
+		},
+	}
+
+	feature.Setup(func(ctx context.Context, t *testing.T, c *envconf.Config) context.Context {
+
+		if err := c.Client().Resources().Create(ctx, etcdClusterSpec); err != nil {
+			t.Fatalf("fail to create Etcd cluster: %s", err)
+		}
+
+		return ctx
+	})
+
+	feature.Assess("statefulSet is not created when etcdCluster.Spec.Size is 0",
+		func(ctx context.Context, t *testing.T, c *envconf.Config) context.Context {
+
+			var etcdCluster ecv1alpha1.EtcdCluster
+			if err := c.Client().Resources().Get(ctx, etcdClusterName, namespace, &etcdCluster); err != nil {
+				t.Fatalf("unable to fetch Etcd cluster: %s", err)
+			}
+
+			var sts appsv1.StatefulSet
+			err := c.Client().Resources().Get(ctx, etcdClusterName, namespace, &sts)
+
+			if !errors.IsNotFound(err) {
+				t.Fatalf("statefulSet found when Etcd Cluster size is zero: %s", err)
+			}
+
+			return ctx
+		},
+	)
+
+	_ = testEnv.Test(t, feature.Feature())
+
+}
+
 func TestClusterHealthy(t *testing.T) {
 	feature := features.New("etcd-operator-controller")