'Test writing a worksheet with no cell data.'

def test_assemble_xml_file(self):

    self.maxDiff = None
    fh = StringIO()
    worksheet = Worksheet()
    worksheet._set_filehandle(fh)
    worksheet.select()
    worksheet.excel_version = 2010
    data = [(-2), 2, 3, (-1), 0]
    worksheet.write_row('A1', data)
    worksheet._assemble_xml_file()
    exp = _xml_to_list('\n                                                                <?xml    version="1.0"    encoding="UTF-8"    standalone="yes"?>\n                                                                <worksheet    xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"    xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    xmlns:x14ac="http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac"    mc:Ignorable="x14ac">\n                                                                        <dimension    ref="A1:E1"/>\n                                                                        <sheetViews>\n                                                                                <sheetView    tabSelected="1"    workbookViewId="0"/>\n                                                                        </sheetViews>\n                                                                        <sheetFormatPr    defaultRowHeight="15"    x14ac:dyDescent="0.25"/>\n                                                                        <sheetData>\n                                                                                <row    r="1"    spans="1:5"    x14ac:dyDescent="0.25">\n                                                                                        <c    r="A1">\n                                                                                                <v>-2</v>\n                                                                                        </c>\n                                                                                        <c    r="B1">\n                                                                                                <v>2</v>\n                                                                                        </c>\n                                                                                        <c    r="C1">\n                                                                                                <v>3</v>\n                                                                                        </c>\n                                                                                        <c    r="D1">\n                                                                                                <v>-1</v>\n                                                                                        </c>\n                                                                                        <c    r="E1">\n                                                                                                <v>0</v>\n                                                                                        </c>\n                                                                                </row>\n                                                                        </sheetData>\n                                                                        <pageMargins    left="0.7"    right="0.7"    top="0.75"    bottom="0.75"    header="0.3"    footer="0.3"/>\n                                                                </worksheet>\n                                                                ')
    got = _xml_to_list(fh.getvalue())
    self.assertEqual(got, exp)
