Roll back pkg client code for Velero server

Signed-off-by: danfengl <danfengl@vmware.com>

test/e2e/pkg/client/client_test.go

@@ -0,0 +1,51 @@
+/*
+Copyright 2018 the Velero contributors.
+
+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 client
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuildUserAgent(t *testing.T) {
+	tests := []struct {
+		name     string
+		command  string
+		os       string
+		arch     string
+		gitSha   string
+		version  string
+		expected string
+	}{
+		{
+			name:     "Test general interpolation in correct order",
+			command:  "velero",
+			os:       "darwin",
+			arch:     "amd64",
+			gitSha:   "abc123",
+			version:  "v0.1.1",
+			expected: "velero/v0.1.1 (darwin/amd64) abc123",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			resp := buildUserAgent(test.command, test.version, test.gitSha, test.os, test.arch)
+			assert.Equal(t, resp, test.expected)
+		})
+	}
+}