[#205] Add md5 checksum in header

Signed-off-by: Marina Biryukova <m.biryukova@yadro.com>

api/handler/multipart_upload_test.go

@@ -2,6 +2,8 @@ package handler
 
 import (
 	"bytes"
+	"crypto/md5"
+	"encoding/hex"
 	"encoding/xml"
 	"fmt"
 	"net/http"
@@ -276,6 +278,33 @@ func TestMultipartUploadWithContentLanguage(t *testing.T) {
 	require.Equal(t, exceptedContentLanguage, w.Header().Get(api.ContentLanguage))
 }
 
+func TestMultipartUploadEnabledMD5(t *testing.T) {
+	hc := prepareHandlerContext(t)
+	hc.config.md5Enabled = true
+	hc.layerFeatures.SetMD5Enabled(true)
+
+	bktName, objName := "bucket-md5", "object-md5"
+	createTestBucket(hc, bktName)
+
+	partSize := 5 * 1024 * 1024
+	multipartUpload := createMultipartUpload(hc, bktName, objName, map[string]string{})
+	etag1, partBody1 := uploadPart(hc, bktName, objName, multipartUpload.UploadID, 1, partSize)
+	md5Sum1 := md5.Sum(partBody1)
+	require.Equal(t, hex.EncodeToString(md5Sum1[:]), etag1)
+
+	etag2, partBody2 := uploadPart(hc, bktName, objName, multipartUpload.UploadID, 2, partSize)
+	md5Sum2 := md5.Sum(partBody2)
+	require.Equal(t, hex.EncodeToString(md5Sum2[:]), etag2)
+
+	w := completeMultipartUploadBase(hc, bktName, objName, multipartUpload.UploadID, []string{etag1, etag2})
+	assertStatus(t, w, http.StatusOK)
+	resp := &CompleteMultipartUploadResponse{}
+	err := xml.NewDecoder(w.Result().Body).Decode(resp)
+	require.NoError(t, err)
+	completeMD5Sum := md5.Sum(append(md5Sum1[:], md5Sum2[:]...))
+	require.Equal(t, hex.EncodeToString(completeMD5Sum[:])+"-2", resp.ETag)
+}
+
 func uploadPartCopy(hc *handlerContext, bktName, objName, uploadID string, num int, srcObj string, start, end int) *UploadPartCopyResponse {
 	return uploadPartCopyBase(hc, bktName, objName, false, uploadID, num, srcObj, start, end)
 }