// We must not use the http.Header().Set method here because some (broken)
	// clients expect the ETag header key to be literally "ETag" - not "Etag" (case-sensitive).
	// Therefore, we have to set the ETag directly as map entry.
	if objInfo.ETag != "" && !del {
		w.Header()[xhttp.ETag] = []string{`"` + objInfo.ETag + `"`}
	}

	// Set the relevant version ID as part of the response header.

		{[]CompletePart{{ETag: "wrong-md5-hash-string"}}, "0deb8cb07527b4b2669c861cb9653607-1", ""},

		// Single CompletePart with valid MD5 hash string.
		{[]CompletePart{{ETag: "cf1f738a5924e645913c984e0fe3d708"}}, "10dc1617fbcf0bd0858048cb96e6bd77-1", ""},

		// Multiple CompletePart with valid MD5 hash string.

// generates CopyObjectResponse from etag and lastModified time.
func generateCopyObjectResponse(etag string, lastModified time.Time) CopyObjectResponse {
	return CopyObjectResponse{
		ETag:         "\"" + etag + "\"",
		LastModified: amztime.ISO8601Format(lastModified.UTC()),
	}
}

// generates CopyObjectPartResponse from etag and lastModified time.

		ETag:       "",
		ShouldFail: true, // ETag prefix is not a valid hex value
	},
	{
		ObjectKey:  [32]byte{},
		ObjectInfo: ObjectInfo{ETag: "16516b396f0f4d4f2a0e7177557bec4-1-2"},
		ETag:       "",
		ShouldFail: true, // ETag contains multiple: -
	},
}

func TestDecryptETag(t *testing.T) {
	for i, test := range decryptETagTests {

			if _, ok := crypto.IsEncrypted(batch[i].UserDefined); ok {
				ETag, err := etag.Parse(batch[i].ETag)
				if err != nil {
					return err
				}
				if SSES3SinglePartObjects[i] {
					ETag, err = etag.Decrypt(keys[0][:], ETag)
					if err != nil {
						return err
					}
					keys = keys[1:]
				}
				batch[i].ETag = ETag.Format().String()
			}
		}
		objects = objects[N:]
	}
	return nil

				PartNumber: part.PartNumber,
				GotETag:    part.ETag,
			}
			return oi, invp
		}
		expPart := currentFI.Parts[partIdx]

		// ensure that part ETag is canonicalized to strip off extraneous quotes
		part.ETag = canonicalizeETag(part.ETag)
		expETag := tryDecryptETag(objectEncryptionKey, expPart.ETag, kind == crypto.S3)
		if expETag != part.ETag {
			invp := InvalidPart{
				PartNumber: part.PartNumber,

		etag = commonETag(etags, quorum)

		if etag != "" { // allow this fallback only if a non-empty etag is found.
			for index, e := range etags {
				if partsMetadata[index].IsValid() && e == etag {
					onlineDisks[index] = disks[index]
				} else {
					onlineDisks[index] = nil
				}
			}
			return onlineDisks, modTime, etag
		}
	}

	PART_ETAG=$(echo "${UPLOAD_PART_OUT}" | jq '.ETag')
	if [ "${idx}" == 10 ]; then
		PARTS="${PARTS}{\"ETag\": ${PART_ETAG}, \"ChecksumSHA256\": \"${PART_CHKSUM}\", \"PartNumber\": ${idx}}"
	else
		PARTS="${PARTS}{\"ETag\": ${PART_ETAG}, \"ChecksumSHA256\": \"${PART_CHKSUM}\", \"PartNumber\": ${idx}},"
	fi
done

					}
					//  Asserting the ETag in the PartInfo.
					if actualMetaData.ETag != expectedResult.Parts[j].ETag {
						t.Errorf("Test %d: %s: Part %d: Expected Etag to be \"%s\", but instead found \"%s\"", i+1, instanceType, j+1, expectedResult.Parts[j].ETag, actualMetaData.ETag)
					}
				}
			}
		}
	}
}

func TestCanonicalizeETag(t *testing.T) {
	testCases := []struct {
		etag              string
		canonicalizedETag string
	}{
		{
			etag:              "\"\"\"",
			canonicalizedETag: "",
		},
		{
			etag:              "\"\"\"abc\"",
			canonicalizedETag: "abc",
		},
		{
			etag:              "abcd",
			canonicalizedETag: "abcd",
		},
		{
			etag:              "abcd\"\"",
			canonicalizedETag: "abcd",
		},
	}