if n != 10 || err != nil {
		t.Fatalf("Write returned (%v, %v), want (10, nil)", n, err)
	}

	// Use ReadFrom to read in some data.
	n2, err := w.ReadFrom(strings.NewReader("abcdef"))
	if n2 != 6 || err != nil {
		t.Fatalf("ReadFrom returned (%v, %v), want (6, nil)", n2, err)
	}
}

type emptyThenNonEmptyReader struct {
	r io.Reader
	n int
}

		}

		uploadIDs = append(uploadIDs, res.UploadID)
	}

	// Parts with size greater than 5 MiB.
	// Generating a 6 MiB byte array.
	validPart := bytes.Repeat([]byte("abcdef"), 1*humanize.MiByte)
	validPartMD5 := getMD5Hash(validPart)
	// Create multipart parts.
	// Need parts to be uploaded before CompleteMultiPartUpload can be called tested.
	parts := []struct {