'Test writing formulas with strings_to_formulas on.'

def test_write_formula_implicit(self):

    workbook = Workbook(self.got_filename, {'strings_to_formulas': True})
    worksheet = workbook.add_worksheet()
    worksheet.write(0, 0, '=1+1', None, 2)
    worksheet.write_string(1, 0, '=1+1')
    workbook.close()
    self.assertExcelEqual()
