'Test the _write_calc_pr() method with the calculation mode set to
manual.'

def test_calc_mode_manual(self):

    self.workbook.set_calc_mode('manual')
    self.workbook._write_calc_pr()
    exp = '<calcPr    calcId="124519"    calcMode="manual"    calcOnSave="0"/>'
    got = self.fh.getvalue()
    self.assertEqual(got, exp)
