Add e2e test for server snippet

Adds the e2e test for server snippet. Similar test to the
configuration snippet. Part of the #3124 effort.

test/e2e/annotations/serversnippet.go

@@ -0,0 +1,57 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package annotations
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"k8s.io/ingress-nginx/test/e2e/framework"
+	"strings"
+)
+
+var _ = framework.IngressNginxDescribe("Annotations - ServerSnippet", func() {
+	f := framework.NewDefaultFramework("serversnippet")
+
+	BeforeEach(func() {
+		err := f.NewEchoDeploymentWithReplicas(2)
+		Expect(err).NotTo(HaveOccurred())
+	})
+
+	AfterEach(func() {
+	})
+
+	It(`add valid directives to server via server snippet"`, func() {
+		host := "serversnippet.foo.com"
+		annotations := map[string]string{
+			"nginx.ingress.kubernetes.io/server-snippet": `
+				more_set_headers "Content-Length: $content_length";
+				more_set_headers "Content-Type: $content_type";`,
+		}
+
+		ing := framework.NewSingleIngress(host, "/", host, f.IngressController.Namespace, "http-svc", 80, &annotations)
+		_, err := f.EnsureIngress(ing)
+
+		Expect(err).NotTo(HaveOccurred())
+		Expect(ing).NotTo(BeNil())
+
+		err = f.WaitForNginxServer(host,
+			func(server string) bool {
+				return strings.Contains(server, `more_set_headers "Content-Length: $content_length`) && strings.Contains(server, `more_set_headers "Content-Type: $content_type";`)
+			})
+		Expect(err).NotTo(HaveOccurred())
+	})
+})