'Test the _write_row() method'

def test_write_row_5(self):

    cell_format = Format({'xf_index': 1})
    self.worksheet._write_row(6, None, [15, cell_format, 0, 0, 0])
    exp = '<row    r="7"    s="1"    customFormat="1">'
    got = self.fh.getvalue()
    self.assertEqual(got, exp)
