if !errors.Is(err, io.ErrUnexpectedEOF) {
		t.Errorf("Expected io.ErrUnexpectedEOF, but got %v", err)
	}
	if written != 5 {
		t.Errorf("Expected written to be '5', but got %v", written)
	}

	f.Seek(0, io.SeekStart)
	r.Seek(0, io.SeekStart)

	written, err = CopyAligned(f, r, *bufp, r.Size(), f)
	if !errors.Is(err, nil) {
		t.Errorf("Expected nil, but got %v", err)
	}
	if written != r.Size() {