azureblob, b2, drive: implement set upload cutoff for chunked upload tests

backend/drive/drive.go

@@ -806,6 +806,18 @@ func (f *Fs) setUploadChunkSize(cs fs.SizeSuffix) (old fs.SizeSuffix, err error)
 	return
 }
 
+func checkUploadCutoff(cs fs.SizeSuffix) error {
+	return nil
+}
+
+func (f *Fs) setUploadCutoff(cs fs.SizeSuffix) (old fs.SizeSuffix, err error) {
+	err = checkUploadCutoff(cs)
+	if err == nil {
+		old, f.opt.UploadCutoff = f.opt.UploadCutoff, cs
+	}
+	return
+}
+
 // NewFs contstructs an Fs from the path, container:path
 func NewFs(name, path string, m configmap.Mapper) (fs.Fs, error) {
 	// Parse config into Options struct
@@ -814,6 +826,10 @@ func NewFs(name, path string, m configmap.Mapper) (fs.Fs, error) {
 	if err != nil {
 		return nil, err
 	}
+	err = checkUploadCutoff(opt.UploadCutoff)
+	if err != nil {
+		return nil, errors.Wrap(err, "drive: upload cutoff")
+	}
 	err = checkUploadChunkSize(opt.ChunkSize)
 	if err != nil {
 		return nil, errors.Wrap(err, "drive: chunk size")

backend/drive/drive_test.go

@@ -24,4 +24,11 @@ func (f *Fs) SetUploadChunkSize(cs fs.SizeSuffix) (fs.SizeSuffix, error) {
 	return f.setUploadChunkSize(cs)
 }
 
-var _ fstests.SetUploadChunkSizer = (*Fs)(nil)
+func (f *Fs) SetUploadCutoff(cs fs.SizeSuffix) (fs.SizeSuffix, error) {
+	return f.setUploadCutoff(cs)
+}
+
+var (
+	_ fstests.SetUploadChunkSizer = (*Fs)(nil)
+	_ fstests.SetUploadCutoffer   = (*Fs)(nil)
+)