e2e: idempotent namespace creation

We create a test namespace once in the management cluster, and once in
the application cluster. Sometimes, in development, both of these happen
to be the same, so the second time we try to create the ns it'll error
out with "namespace foobar already exists", so if that happens we'll
just ignore it.

test/e2e/e2e_util.go

@@ -284,12 +284,24 @@ func poll(timeout time.Duration, waitCondition func() (bool, error)) error {
 
 func setupNamespace(name string) (*corev1.Namespace, error) {
 	newNs := testNamespace(name)
-	_, err := appKubeClient.CoreV1().Namespaces().Create(newNs)
+
+	// We create a test namespace once in the management cluster, and once
+	// in the application cluster. Sometimes, in development, both of these
+	// happen to be the same, so the second time we try to create the ns
+	// it'll error out with "namespace foobar already exists", so if that
+	// happens we'll just ignore it.
+
+	ns, err := appKubeClient.CoreV1().Namespaces().Create(newNs)
 	if err != nil {
 		return nil, err
 	}
 
-	return kubeClient.CoreV1().Namespaces().Create(newNs)
+	_, err = kubeClient.CoreV1().Namespaces().Create(newNs)
+	if err != nil && !errors.IsAlreadyExists(err) {
+		return nil, err
+	}
+
+	return ns, nil
 }
 
 func teardownNamespace(name string) {