@@ -281,12 +281,12 @@ func requiresAuth(w http.ResponseWriter, r *http.Request) bool {

 		return true

 	}

 	w.Header().Add("WWW-Authenticate", "token")

-	apiError(w, "Wrong auth", 401)

+	apiError(w, "Wrong auth", http.StatusUnauthorized)

 	return false

 }

 func handlerGetPing(w http.ResponseWriter, r *http.Request) {

-	writeResponse(w, true, 200)

+	writeResponse(w, true, http.StatusOK)

 }

 func handlerGetImage(w http.ResponseWriter, r *http.Request) {

@@ -323,17 +323,17 @@ func handlerPutImage(w http.ResponseWriter, r *http.Request) {

 	}

 	if checksum := r.Header.Get("X-Docker-Checksum"); checksum != "" {

 		if checksum != layer["checksum_simple"] && checksum != layer["checksum_tarsum"] {

-			apiError(w, "Wrong checksum", 400)

+			apiError(w, "Wrong checksum", http.StatusBadRequest)

 			return

 		}

 	}

 	body, err := ioutil.ReadAll(r.Body)

 	if err != nil {

-		apiError(w, fmt.Sprintf("Error: %s", err), 500)

+		apiError(w, fmt.Sprintf("Error: %s", err), http.StatusInternalServerError)

 		return

 	}

 	layer[action] = string(body)

-	writeResponse(w, true, 200)

+	writeResponse(w, true, http.StatusOK)

 }

 func handlerGetDeleteTags(w http.ResponseWriter, r *http.Request) {

@@ -342,20 +342,20 @@ func handlerGetDeleteTags(w http.ResponseWriter, r *http.Request) {

 	}

 	repositoryName, err := reference.WithName(mux.Vars(r)["repository"])

 	if err != nil {

-		apiError(w, "Could not parse repository", 400)

+		apiError(w, "Could not parse repository", http.StatusBadRequest)

 		return

 	}

 	tags, exists := testRepositories[repositoryName.String()]

 	if !exists {

-		apiError(w, "Repository not found", 404)

+		apiError(w, "Repository not found", http.StatusNotFound)

 		return

 	}

 	if r.Method == http.MethodDelete {

 		delete(testRepositories, repositoryName.String())

-		writeResponse(w, true, 200)

+		writeResponse(w, true, http.StatusOK)

 		return

 	}

-	writeResponse(w, tags, 200)

+	writeResponse(w, tags, http.StatusOK)

 }

 func handlerGetTag(w http.ResponseWriter, r *http.Request) {

@@ -365,21 +365,21 @@ func handlerGetTag(w http.ResponseWriter, r *http.Request) {

 	vars := mux.Vars(r)

 	repositoryName, err := reference.WithName(vars["repository"])

 	if err != nil {

-		apiError(w, "Could not parse repository", 400)

+		apiError(w, "Could not parse repository", http.StatusBadRequest)

 		return

 	}

 	tagName := vars["tag"]

 	tags, exists := testRepositories[repositoryName.String()]

 	if !exists {

-		apiError(w, "Repository not found", 404)

+		apiError(w, "Repository not found", http.StatusNotFound)

 		return

 	}

 	tag, exists := tags[tagName]

 	if !exists {

-		apiError(w, "Tag not found", 404)

+		apiError(w, "Tag not found", http.StatusNotFound)

 		return

 	}

-	writeResponse(w, tag, 200)

+	writeResponse(w, tag, http.StatusOK)

 }

 func handlerPutTag(w http.ResponseWriter, r *http.Request) {

@@ -389,7 +389,7 @@ func handlerPutTag(w http.ResponseWriter, r *http.Request) {

 	vars := mux.Vars(r)

 	repositoryName, err := reference.WithName(vars["repository"])

 	if err != nil {

-		apiError(w, "Could not parse repository", 400)

+		apiError(w, "Could not parse repository", http.StatusBadRequest)

 		return

 	}

 	tagName := vars["tag"]

@@ -401,15 +401,15 @@ func handlerPutTag(w http.ResponseWriter, r *http.Request) {

 	tagValue := ""

 	readJSON(r, tagValue)

 	tags[tagName] = tagValue

-	writeResponse(w, true, 200)

+	writeResponse(w, true, http.StatusOK)

 }

 func handlerUsers(w http.ResponseWriter, r *http.Request) {

-	code := 200

+	code := http.StatusOK

 	if r.Method == http.MethodPost {

-		code = 201

+		code = http.StatusCreated

 	} else if r.Method == http.MethodPut {

-		code = 204

+		code = http.StatusNoContent

 	}

 	writeResponse(w, "", code)

 }

@@ -420,14 +420,14 @@ func handlerImages(w http.ResponseWriter, r *http.Request) {

 	w.Header().Add("X-Docker-Token", fmt.Sprintf("FAKE-SESSION-%d", time.Now().UnixNano()))

 	if r.Method == http.MethodPut {

 		if strings.HasSuffix(r.URL.Path, "images") {

-			writeResponse(w, "", 204)

+			writeResponse(w, "", http.StatusNoContent)

 			return

 		}

-		writeResponse(w, "", 200)

+		writeResponse(w, "", http.StatusOK)

 		return

 	}

 	if r.Method == http.MethodDelete {

-		writeResponse(w, "", 204)

+		writeResponse(w, "", http.StatusNoContent)

 		return

 	}

 	var images []map[string]string

@@ -438,11 +438,11 @@ func handlerImages(w http.ResponseWriter, r *http.Request) {

 		image["Tag"] = "latest"

 		images = append(images, image)

 	}

-	writeResponse(w, images, 200)

+	writeResponse(w, images, http.StatusOK)

 }

 func handlerAuth(w http.ResponseWriter, r *http.Request) {

-	writeResponse(w, "OK", 200)

+	writeResponse(w, "OK", http.StatusOK)

 }

 func handlerSearch(w http.ResponseWriter, r *http.Request) {

@@ -451,7 +451,7 @@ func handlerSearch(w http.ResponseWriter, r *http.Request) {

 		NumResults: 1,

 		Results:    []registrytypes.SearchResult{{Name: "fakeimage", StarCount: 42}},

 	}

-	writeResponse(w, result, 200)

+	writeResponse(w, result, http.StatusOK)

 }

 func TestPing(t *testing.T) {

@@ -459,7 +459,7 @@ func TestPing(t *testing.T) {

 	if err != nil {

 		t.Fatal(err)

 	}

-	assertEqual(t, res.StatusCode, 200, "")

+	assertEqual(t, res.StatusCode, http.StatusOK, "")

 	assertEqual(t, res.Header.Get("X-Docker-Registry-Config"), "mock",

 		"This is not a Mocked Registry")

 }

@@ -56,10 +56,10 @@ func (r *requestReader) Read(p []byte) (n int, err error) {

 		r.cleanUpResponse()

 		return 0, err

 	}

-	if r.currentResponse.StatusCode == 416 && r.lastRange == r.totalSize && r.currentResponse.ContentLength == 0 {

+	if r.currentResponse.StatusCode == http.StatusRequestedRangeNotSatisfiable && r.lastRange == r.totalSize && r.currentResponse.ContentLength == 0 {

 		r.cleanUpResponse()

 		return 0, io.EOF

-	} else if r.currentResponse.StatusCode != 206 && r.lastRange != 0 && isFreshRequest {

+	} else if r.currentResponse.StatusCode != http.StatusPartialContent && r.lastRange != 0 && isFreshRequest {

 		r.cleanUpResponse()

 		return 0, fmt.Errorf("the server doesn't support byte ranges")

 	}

@@ -99,7 +99,7 @@ func TestResumableRequestReaderWithReadError(t *testing.T) {

 	response := &http.Response{

 		Status:        "500 Internal Server",

-		StatusCode:    500,

+		StatusCode:    http.StatusInternalServerError,

 		ContentLength: 0,

 		Close:         true,

 		Body:          errorReaderCloser{},

@@ -130,7 +130,7 @@ func TestResumableRequestReaderWithEOFWith416Response(t *testing.T) {

 	response := &http.Response{

 		Status:        "416 Requested Range Not Satisfiable",

-		StatusCode:    416,

+		StatusCode:    http.StatusRequestedRangeNotSatisfiable,

 		ContentLength: 0,

 		Close:         true,

 		Body:          ioutil.NopCloser(strings.NewReader("")),

@@ -225,8 +225,8 @@ func (r *Session) GetRemoteHistory(imgID, registry string) ([]string, error) {

 		return nil, err

 	}

 	defer res.Body.Close()

-	if res.StatusCode != 200 {

-		if res.StatusCode == 401 {

+	if res.StatusCode != http.StatusOK {

+		if res.StatusCode == http.StatusUnauthorized {

 			return nil, errcode.ErrorCodeUnauthorized.WithArgs()

 		}

 		return nil, newJSONError(fmt.Sprintf("Server error: %d trying to fetch remote history for %s", res.StatusCode, imgID), res)

@@ -248,7 +248,7 @@ func (r *Session) LookupRemoteImage(imgID, registry string) error {

 		return err

 	}

 	res.Body.Close()

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		return newJSONError(fmt.Sprintf("HTTP code %d", res.StatusCode), res)

 	}

 	return nil

@@ -261,7 +261,7 @@ func (r *Session) GetRemoteImageJSON(imgID, registry string) ([]byte, int64, err

 		return nil, -1, fmt.Errorf("Failed to download json: %s", err)

 	}

 	defer res.Body.Close()

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		return nil, -1, newJSONError(fmt.Sprintf("HTTP code %d", res.StatusCode), res)

 	}

 	// if the size header is not present, then set it to '-1'

@@ -308,7 +308,7 @@ func (r *Session) GetRemoteImageLayer(imgID, registry string, imgSize int64) (io

 			statusCode, imgID)

 	}

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		res.Body.Close()

 		return nil, fmt.Errorf("Server error: Status %d while fetching image layer (%s)",

 			res.StatusCode, imgID)

@@ -347,7 +347,7 @@ func (r *Session) GetRemoteTag(registries []string, repositoryRef reference.Name

 		if res.StatusCode == 404 {

 			return "", ErrRepoNotFound

 		}

-		if res.StatusCode != 200 {

+		if res.StatusCode != http.StatusOK {

 			continue

 		}

@@ -385,7 +385,7 @@ func (r *Session) GetRemoteTags(registries []string, repositoryRef reference.Nam

 		if res.StatusCode == 404 {

 			return nil, ErrRepoNotFound

 		}

-		if res.StatusCode != 200 {

+		if res.StatusCode != http.StatusOK {

 			continue

 		}

@@ -441,14 +441,14 @@ func (r *Session) GetRepositoryData(name reference.Named) (*RepositoryData, erro

 		return nil, fmt.Errorf("Error while pulling image: %v", err)

 	}

 	defer res.Body.Close()

-	if res.StatusCode == 401 {

+	if res.StatusCode == http.StatusUnauthorized {

 		return nil, errcode.ErrorCodeUnauthorized.WithArgs()

 	}

 	// TODO: Right now we're ignoring checksums in the response body.

 	// In the future, we need to use them to check image validity.

 	if res.StatusCode == 404 {

 		return nil, newJSONError(fmt.Sprintf("HTTP code: %d", res.StatusCode), res)

-	} else if res.StatusCode != 200 {

+	} else if res.StatusCode != http.StatusOK {

 		errBody, err := ioutil.ReadAll(res.Body)

 		if err != nil {

 			logrus.Debugf("Error reading response body: %s", err)

@@ -505,7 +505,7 @@ func (r *Session) PushImageChecksumRegistry(imgData *ImgData, registry string) e

 	if len(res.Cookies()) > 0 {

 		r.client.Jar.SetCookies(req.URL, res.Cookies())

 	}

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		errBody, err := ioutil.ReadAll(res.Body)

 		if err != nil {

 			return fmt.Errorf("HTTP code %d while uploading metadata and error when trying to parse response body: %s", res.StatusCode, err)

@@ -539,10 +539,10 @@ func (r *Session) PushImageJSONRegistry(imgData *ImgData, jsonRaw []byte, regist

 		return fmt.Errorf("Failed to upload metadata: %s", err)

 	}

 	defer res.Body.Close()

-	if res.StatusCode == 401 && strings.HasPrefix(registry, "http://") {

+	if res.StatusCode == http.StatusUnauthorized && strings.HasPrefix(registry, "http://") {

 		return newJSONError("HTTP code 401, Docker will not send auth headers over HTTP.", res)

 	}

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		errBody, err := ioutil.ReadAll(res.Body)

 		if err != nil {

 			return newJSONError(fmt.Sprintf("HTTP code %d while uploading metadata and error when trying to parse response body: %s", res.StatusCode, err), res)

@@ -591,7 +591,7 @@ func (r *Session) PushImageLayerRegistry(imgID string, layer io.Reader, registry

 	}

 	defer res.Body.Close()

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		errBody, err := ioutil.ReadAll(res.Body)

 		if err != nil {

 			return "", "", newJSONError(fmt.Sprintf("HTTP code %d while uploading metadata and error when trying to parse response body: %s", res.StatusCode, err), res)

@@ -621,7 +621,7 @@ func (r *Session) PushRegistryTag(remote reference.Named, revision, tag, registr

 		return err

 	}

 	res.Body.Close()

-	if res.StatusCode != 200 && res.StatusCode != 201 {

+	if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusCreated {

 		return newJSONError(fmt.Sprintf("Internal server error: %d trying to push tag %s on %s", res.StatusCode, tag, reference.Path(remote)), res)

 	}

 	return nil

@@ -675,13 +675,13 @@ func (r *Session) PushImageJSONIndex(remote reference.Named, imgList []*ImgData,

 	}

 	defer res.Body.Close()

-	if res.StatusCode == 401 {

+	if res.StatusCode == http.StatusUnauthorized {

 		return nil, errcode.ErrorCodeUnauthorized.WithArgs()

 	}

 	var tokens, endpoints []string

 	if !validate {

-		if res.StatusCode != 200 && res.StatusCode != 201 {

+		if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusCreated {

 			errBody, err := ioutil.ReadAll(res.Body)

 			if err != nil {

 				logrus.Debugf("Error reading response body: %s", err)

@@ -699,7 +699,7 @@ func (r *Session) PushImageJSONIndex(remote reference.Named, imgList []*ImgData,

 			return nil, err

 		}

 	} else {

-		if res.StatusCode != 204 {

+		if res.StatusCode != http.StatusNoContent {

 			errBody, err := ioutil.ReadAll(res.Body)

 			if err != nil {

 				logrus.Debugf("Error reading response body: %s", err)

@@ -752,7 +752,7 @@ func (r *Session) SearchRepositories(term string, limit int) (*registrytypes.Sea

 		return nil, errdefs.System(err)

 	}

 	defer res.Body.Close()

-	if res.StatusCode != 200 {

+	if res.StatusCode != http.StatusOK {

 		return nil, newJSONError(fmt.Sprintf("Unexpected status code %d", res.StatusCode), res)

 	}

 	result := new(registrytypes.SearchResults)