Squashed commit of the following:

commit 5a268dbafb9318b888142931ea27a1af10b9a8e7
Author: Marius <maerious@gmail.com>
Date:   Wed Jul 19 11:47:26 2017 +0200

    Remove manual assignment of upload ID in S3Store

commit a37e149090ee7fd5f170d24ccc33b8af9ae18fae
Author: Marius <maerious@gmail.com>
Date:   Wed Jul 19 11:42:00 2017 +0200

    Format Go code

commit 6643a9be62
Author: Markus Kienast <mark@rickkiste.at>
Date:   Sun Jul 16 17:08:24 2017 +0200

    fixed ID value in .info; adjusted tests; fixed assert(expected, received) swap

s3store/s3store.go

@@ -168,25 +168,10 @@ func (store S3Store) NewUpload(info tusd.FileInfo) (id string, err error) {
 	if info.ID == "" {
 		uploadId = uid.Uid()
 	} else {
+		// certain tests set info.ID in advance
 		uploadId = info.ID
 	}
 
-	infoJson, err := json.Marshal(info)
-	if err != nil {
-		return "", err
-	}
-
-	// Create object on S3 containing information about the file
-	_, err = store.Service.PutObject(&s3.PutObjectInput{
-		Bucket:        aws.String(store.Bucket),
-		Key:           aws.String(uploadId + ".info"),
-		Body:          bytes.NewReader(infoJson),
-		ContentLength: aws.Int64(int64(len(infoJson))),
-	})
-	if err != nil {
-		return "", fmt.Errorf("s3store: unable to create info file:\n%s", err)
-	}
-
 	// Convert meta data into a map of pointers for AWS Go SDK, sigh.
 	metadata := make(map[string]*string, len(info.MetaData))
 	for key, value := range info.MetaData {
@@ -207,8 +192,25 @@ func (store S3Store) NewUpload(info tusd.FileInfo) (id string, err error) {
 	}
 
 	id = uploadId + "+" + *res.UploadId
+	info.ID = id
 
-	return
+	infoJson, err := json.Marshal(info)
+	if err != nil {
+		return "", err
+	}
+
+	// Create object on S3 containing information about the file
+	_, err = store.Service.PutObject(&s3.PutObjectInput{
+		Bucket:        aws.String(store.Bucket),
+		Key:           aws.String(uploadId + ".info"),
+		Body:          bytes.NewReader(infoJson),
+		ContentLength: aws.Int64(int64(len(infoJson))),
+	})
+	if err != nil {
+		return "", fmt.Errorf("s3store: unable to create info file:\n%s", err)
+	}
+
+	return id, nil
 }
 
 func (store S3Store) WriteChunk(id string, offset int64, src io.Reader) (int64, error) {
@@ -305,11 +307,6 @@ func (store S3Store) GetInfo(id string) (info tusd.FileInfo, err error) {
 		return info, err
 	}
 
-	// The JSON object stored on S3 does not contain the proper upload ID because
-	// the ID has constructed after the storing happened. Therefore we set it
-	// manually.
-	info.ID = id
-
 	// Get uploaded parts and their offset
 	listPtr, err := store.Service.ListParts(&s3.ListPartsInput{
 		Bucket:   aws.String(store.Bucket),

s3store/s3store_test.go

@@ -32,19 +32,13 @@ func TestNewUpload(t *testing.T) {
 	s3obj := NewMockS3API(mockCtrl)
 	store := s3store.New("bucket", s3obj)
 
-	assert.Equal(store.Bucket, "bucket")
+	assert.Equal("bucket", store.Bucket)
-	assert.Equal(store.Service, s3obj)
+	assert.Equal(s3obj, store.Service)
 
 	s1 := "hello"
 	s2 := "men?"
 
 	gomock.InOrder(
-		s3obj.EXPECT().PutObject(&s3.PutObjectInput{
-			Bucket:        aws.String("bucket"),
-			Key:           aws.String("uploadId.info"),
-			Body:          bytes.NewReader([]byte(`{"ID":"uploadId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`)),
-			ContentLength: aws.Int64(int64(136)),
-		}),
 		s3obj.EXPECT().CreateMultipartUpload(&s3.CreateMultipartUploadInput{
 			Bucket: aws.String("bucket"),
 			Key:    aws.String("uploadId"),
@@ -55,6 +49,12 @@ func TestNewUpload(t *testing.T) {
 		}).Return(&s3.CreateMultipartUploadOutput{
 			UploadId: aws.String("multipartId"),
 		}, nil),
+		s3obj.EXPECT().PutObject(&s3.PutObjectInput{
+			Bucket:        aws.String("bucket"),
+			Key:           aws.String("uploadId.info"),
+			Body:          bytes.NewReader([]byte(`{"ID":"uploadId+multipartId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`)),
+			ContentLength: aws.Int64(int64(148)),
+		}),
 	)
 
 	info := tusd.FileInfo{
@@ -68,7 +68,7 @@ func TestNewUpload(t *testing.T) {
 
 	id, err := store.NewUpload(info)
 	assert.Nil(err)
-	assert.Equal(id, "uploadId+multipartId")
+	assert.Equal("uploadId+multipartId", id)
 }
 
 func TestGetInfoNotFound(t *testing.T) {
@@ -85,7 +85,7 @@ func TestGetInfoNotFound(t *testing.T) {
 	}).Return(nil, awserr.New("NoSuchKey", "The specified key does not exist.", nil))
 
 	_, err := store.GetInfo("uploadId+multipartId")
-	assert.Equal(err, tusd.ErrNotFound)
+	assert.Equal(tusd.ErrNotFound, err)
 }
 
 func TestGetInfo(t *testing.T) {
@@ -101,7 +101,7 @@ func TestGetInfo(t *testing.T) {
 			Bucket: aws.String("bucket"),
 			Key:    aws.String("uploadId.info"),
 		}).Return(&s3.GetObjectOutput{
-			Body: ioutil.NopCloser(bytes.NewReader([]byte(`{"ID":"uploadId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`))),
+			Body: ioutil.NopCloser(bytes.NewReader([]byte(`{"ID":"uploadId+multipartId","Size":500,"Offset":0,"MetaData":{"bar":"menü","foo":"hello"},"IsPartial":false,"IsFinal":false,"PartialUploads":null}`))),
 		}, nil),
 		s3obj.EXPECT().ListParts(&s3.ListPartsInput{
 			Bucket:   aws.String("bucket"),
@@ -173,7 +173,7 @@ func TestGetReader(t *testing.T) {
 
 	content, err := store.GetReader("uploadId+multipartId")
 	assert.Nil(err)
-	assert.Equal(content, ioutil.NopCloser(bytes.NewReader([]byte(`hello world`))))
+	assert.Equal(ioutil.NopCloser(bytes.NewReader([]byte(`hello world`))), content)
 }
 
 func TestGetReaderNotFound(t *testing.T) {
@@ -199,7 +199,7 @@ func TestGetReaderNotFound(t *testing.T) {
 
 	content, err := store.GetReader("uploadId+multipartId")
 	assert.Nil(content)
-	assert.Equal(err, tusd.ErrNotFound)
+	assert.Equal(tusd.ErrNotFound, err)
 }
 
 func TestGetReaderNotFinished(t *testing.T) {
@@ -227,7 +227,7 @@ func TestGetReaderNotFinished(t *testing.T) {
 
 	content, err := store.GetReader("uploadId+multipartId")
 	assert.Nil(content)
-	assert.Equal(err.Error(), "cannot stream non-finished upload")
+	assert.Equal("cannot stream non-finished upload", err.Error())
 }
 
 func TestFinishUpload(t *testing.T) {