test: more chunked upload tests with different payload types

tests/rest_scripts/command/dataSource.go

@@ -0,0 +1,11 @@
+package command
+
+import "io"
+
+type DataSource interface {
+	SourceDataByteSize() (int64, error)
+	CalculateSHA256HashString() (string, error)
+	Close() error
+	GetReader() (io.Reader, error)
+	GetTeeReader(io.Writer) (io.Reader, error)
+}