'Test writing a drawing with no cell data.'

def test_assemble_xml_file(self):

    self.maxDiff = None
    fh = StringIO()
    drawing = Drawing()
    drawing._set_filehandle(fh)
    drawing._add_drawing_object([1, 4, 8, 457200, 104775, 12, 22, 152400, 180975, None, None, None, None, None, None])
    drawing.embedded = 1
    drawing._assemble_xml_file()
    exp = _xml_to_list('\n                                                                <?xml    version="1.0"    encoding="UTF-8"    standalone="yes"?>\n                                                                <xdr:wsDr    xmlns:xdr="http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing"    xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main">\n                                                                        <xdr:twoCellAnchor>\n                                                                                <xdr:from>\n                                                                                        <xdr:col>4</xdr:col>\n                                                                                        <xdr:colOff>457200</xdr:colOff>\n                                                                                        <xdr:row>8</xdr:row>\n                                                                                        <xdr:rowOff>104775</xdr:rowOff>\n                                                                                </xdr:from>\n                                                                                <xdr:to>\n                                                                                        <xdr:col>12</xdr:col>\n                                                                                        <xdr:colOff>152400</xdr:colOff>\n                                                                                        <xdr:row>22</xdr:row>\n                                                                                        <xdr:rowOff>180975</xdr:rowOff>\n                                                                                </xdr:to>\n                                                                                <xdr:graphicFrame    macro="">\n                                                                                        <xdr:nvGraphicFramePr>\n                                                                                                <xdr:cNvPr    id="2"    name="Chart    1"/>\n                                                                                                <xdr:cNvGraphicFramePr/>\n                                                                                        </xdr:nvGraphicFramePr>\n                                                                                        <xdr:xfrm>\n                                                                                                <a:off    x="0"    y="0"/>\n                                                                                                <a:ext    cx="0"    cy="0"/>\n                                                                                        </xdr:xfrm>\n                                                                                        <a:graphic>\n                                                                                                <a:graphicData    uri="http://schemas.openxmlformats.org/drawingml/2006/chart">\n                                                                                                        <c:chart    xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart"    xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"    r:id="rId1"/>\n                                                                                                </a:graphicData>\n                                                                                        </a:graphic>\n                                                                                </xdr:graphicFrame>\n                                                                                <xdr:clientData/>\n                                                                        </xdr:twoCellAnchor>\n                                                                </xdr:wsDr>\n                                                                ')
    got = _xml_to_list(fh.getvalue())
    self.assertEqual(got, exp)
