Revert of Migrate tsmon protos to proto3

common/tsmon/field/field_test.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 package field
 
 import (
         "fmt"
         "testing"
 
+        "github.com/golang/protobuf/proto"
+
         pb "github.com/luci/luci-go/common/tsmon/ts_mon_proto"
 
         . "github.com/smartystreets/goconvey/convey"
 )
 
 func TestSerialize(t *testing.T) {
         data := []struct {
                 fields []Field
                 values []interface{}
                 want   []*pb.MetricsField
         }{
                 {
                         fields: []Field{String("foo")},
                         values: makeInterfaceSlice("v"),
                         want: []*pb.MetricsField{
                                 {
-                                        Name:        "foo",
-                                        Type:        pb.MetricsField_STRING,
-                                        StringValue: "v",
+                                        Name:        proto.String("foo"),
+                                        Type:        pb.MetricsField_STRING.Enum(),
+                                        StringValue: proto.String("v"),
                                 },
                         },
                 },
                 {
                         fields: []Field{Int("foo")},
                         values: makeInterfaceSlice(int64(123)),
                         want: []*pb.MetricsField{
                                 {
-                                        Name:     "foo",
-                                        Type:     pb.MetricsField_INT,
-                                        IntValue: 123,
+                                        Name:     proto.String("foo"),
+                                        Type:     pb.MetricsField_INT.Enum(),
+                                        IntValue: proto.Int64(123),
                                 },
                         },
                 },
                 {
                         fields: []Field{Bool("foo")},
                         values: makeInterfaceSlice(true),
                         want: []*pb.MetricsField{
                                 {
-                                        Name:      "foo",
-                                        Type:      pb.MetricsField_BOOL,
-                                        BoolValue: true,
+                                        Name:      proto.String("foo"),
+                                        Type:      pb.MetricsField_BOOL.Enum(),
+                                        BoolValue: proto.Bool(true),
                                 },
                         },
                 },
         }
 
         for i, d := range data {
                 Convey(fmt.Sprintf("%d. Serialize(%v, %v)", i, d.fields, d.values), t, func() {
                         got := Serialize(d.fields, d.values)
                         So(got, ShouldResemble, d.want)
                 })
         }
 }