Golangを使ってアプリを開発する際に、 外部環境への依存をテストするときのTIPS集です

1. Golang.tokyo
2018/08/21 (Tue)
( @duck8823 )

2. •
• @duck8823
•
• /
•
• Kotlin
• Golang

3. •
• @duck8823
•
•
•
• Kotlin
• Golang

4. •
• @duck8823
•
•
•
• Kotlin
• Golang

5. CI
• duck8823/duci
• Golang
• Docker

6. CI
• duck8823/duci
• Golang
• Docker

7. CI
• duck8823/duci
• Golang
• Docker

8. Webhooks
(HTTP)
Commit Status
(HTTP)

9. Webhooks
(HTTP)
Commit Status
(HTTP)

10. Webhooks
(HTTP)
Commit Status
(HTTP)

11. ( )
• Incoming HTTP Requests
• Git Docker ( )
•
•
• Outgoing HTTP Requests

13. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

14. Incoming HTTP Requests
func HandlerFunc(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
body, _ := ioutil.ReadAll(r.Body)
w.Write([]byte(fmt.Sprintf("Hello %s.", body)))
}
• HandlerFunc
, . "

15. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}

16. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}
http.ResponseWriter
(*httptest.ResponseRecorder)
*http.Request

17. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}

18. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}
*httptest.ResponseRecorder

19. chi HandlerFunc
• URL ("/{param}") HandlerFunc
go-chi/chi
// "/{param}"
func ChiHandlerFunc(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
param := chi.URLParam(r.Context(), "param")
w.Write([]byte(fmt.Sprintf("Hello %s.", param)))
}

20. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}

21. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}
context.Context

22. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}
*http.Request
context.Context

23. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}

24. Incoming HTTP Requests
• httptest
• URL

25. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

26. Git Docker (3rd )
•
src-d/go-git moby/moby
•
•

27. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

28. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

29. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

30. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

31. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

32. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
} .
•

33. Mock
• *client.Client
type Moby interface {
ImagePull(...) (...)
ContainerCreate(...) (container.ContainerCreateCreatedBody, error)
ContainerStart(...) error
}
type docker struct {
moby Moby
}

34. Mock
• google/mock/gomock
func TestDocker_Run(t *testing.T) {
ctrl := gomock.NewController(t)
mockMoby := NewMockMoby(ctrl)
mockMoby.EXPECT().
ImagePull(gomock.Any(), gomock.Any(), gomock.Any()).
AnyTimes().
Return(nil, errors.New("error image pull"))
docker := &docker{moby: mockMoby}
docker.Run("centos", "echo", "hello world")
}

35. Git Docker (3rd )
•
• gomock
•
( mock )

36. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

37. package logger
var Writer io.Writer = os.Stdout
func Debug(message string) {
fmt.Fprintf(Writer, "[DEBUG] %sn", message)
}
•
• ( os.Stdout ) io.Writer (*os.File )

38. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

39. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}
) (
).(
1
( ( 2

40. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

41. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

42. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

43. • io.Writer
io.Pipe

44. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

45. •
func Debug(message string) {
now := time.Now().Format("2006-01-02 15:04:05")
fmt.Fprintf(Writer, "%s [DEBUG] %sn", now, message)
}

46. time.Now()
•
func Debug(message string) {
now := clock.Now().Format("2006-01-02 15:04:05")
fmt.Fprintf(Writer, "%s [DEBUG] %sn", now, message)
}
package clock
import "time"
var Now = func () time.Time {
return time.Now()
}

47. func TestDebug(t *testing.T) {
// given
jst, _ := time.LoadLocation("Asia/Tokyo")
clock.Now = func() time.Time {
return time.Date(1987, time.March, 27, 09, 34, 00, 00, jst)
}
// and
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "1987-03-27 09:34:00 [DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
// ...
}

48. func TestDebug(t *testing.T) {
// given
jst, _ := time.LoadLocation("Asia/Tokyo")
clock.Now = func() time.Time {
return time.Date(1987, time.March, 27, 09, 34, 00, 00, jst)
}
// and
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "1987-03-27 09:34:00 [DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
// ...
}
.

49. func TestDebug(t *testing.T) {
// given
jst, _ := time.LoadLocation("Asia/Tokyo")
clock.Now = func() time.Time {
return time.Date(1987, time.March, 27, 09, 34, 00, 00, jst)
}
// and
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "1987-03-27 09:34:00 [DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
// ...
}

50. • ( )
• time.Now

51. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

52. Outgoing HTTP Requests
• EO
• IL P
• H / D G RA

53. Outgoing HTTP Requests
• 2 ) ) / ( (
func TestRequest(t *testing.T) {
defer gock.Off()
gock.New("http://example.com").
Post("/").
Reply(http.StatusOK)
resp, _ := http.Post("http://example.com/", "application/json", nil)
if resp.StatusCode != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, resp.StatusCode)
}
}

54. Outgoing HTTP Requests
• 2 ) ) / ( (
func TestRequest(t *testing.T) {
defer gock.Off()
gock.New("http://example.com").
Post("/").
Reply(http.StatusOK)
resp, _ := http.Post("http://example.com/", "application/json", nil)
if resp.StatusCode != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, resp.StatusCode)
}
}

55. Outgoing HTTP Requests
• 2 ) ) / ( (
func TestRequest(t *testing.T) {
defer gock.Off()
gock.New("http://example.com").
Post("/").
Reply(http.StatusOK)
resp, _ := http.Post("http://example.com/", "application/json", nil)
if resp.StatusCode != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, resp.StatusCode)
}
}

56. Outgoing HTTP Requests
•
•

57. Webhooks
(HTTP)
Commit Status
(HTTP)

58. Webhooks
(HTTP)
Commit Status
(HTTP)

59. Webhooks
(HTTP)
Commit Status
(HTTP)

60. Webhooks
(HTTP)
Commit Status
(HTTP)

61. Webhooks
(HTTP)
Commit Status
(HTTP)
)& )
.
& &(

62. Webhooks
(HTTP)
Commit Status
(HTTP)

63. • oc
• H
• ) ( k
• P T
• p
• he ) (M