Add a Go language example.

This follows the other examples so that it can be used as a tutorial,
such as the ones at:
  https://developers.google.com/protocol-buffers/docs/tutorials

Even though Go generally does not use Makefiles, I added targets for the
Go examples to be consistent with the other languages.

Edit:

Fix Travis run. Change to use $HOME instead of ~. Add protoc to path.
GOPATH entry cannot start with shell metacharacter '~': "~/gocode"

Edit(2):

Fix Go code style to address comments.

1 files changed, 58 insertions, 0 deletions

diff --git a/examples/add_person_test.go b/examples/add_person_test.go
new file mode 100644
index 00000000..0507db6f
--- /dev/null
+++ b/examples/add_person_test.go
@@ -0,0 +1,58 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/golang/protobuf/proto"
+	pb "github.com/google/protobuf/examples/tutorial"
+)
+
+func TestPromptForAddressReturnsAddress(t *testing.T) {
+	in := `12345
+Example Name
+name@example.com
+123-456-7890
+home
+222-222-2222
+mobile
+111-111-1111
+work
+777-777-7777
+unknown
+
+`
+	got, err := promptForAddress(strings.NewReader(in))
+	if err != nil {
+		t.Fatalf("promptForAddress(%q) had unexpected error: %s", in, err.Error())
+	}
+	if got.Id != 12345 {
+		t.Errorf("promptForAddress(%q) got %d, want ID %d", in, got.Id, 12345)
+	}
+	if got.Name != "Example Name" {
+		t.Errorf("promptForAddress(%q) => want name %q, got %q", "Example Name", got.Name)
+	}
+	if got.Email != "name@example.com" {
+		t.Errorf("promptForAddress(%q) => want email %q, got %q", "name@example.com", got.Email)
+	}
+
+	want := []*pb.Person_PhoneNumber{
+		{Number: "123-456-7890", Type: pb.Person_HOME},
+		{Number: "222-222-2222", Type: pb.Person_MOBILE},
+		{Number: "111-111-1111", Type: pb.Person_WORK},
+		{Number: "777-777-7777", Type: pb.Person_MOBILE},
+	}
+	if len(got.Phones) != len(want) {
+		t.Errorf("want %d phone numbers, got %d", len(want), len(got.Phones))
+	}
+	phones := len(got.Phones)
+	if phones > len(want) {
+		phones = len(want)
+	}
+	for i := 0; i < phones; i++ {
+		if !proto.Equal(got.Phones[i], want[i]) {
+			t.Errorf("want phone %q, got %q", *want[i], *got.Phones[i])
+		}
+
+	}
+}