'Test writing a vml with no cell data.'

def test_assemble_xml_file(self):

    self.maxDiff = None
    fh = StringIO()
    vml = Vml()
    vml._set_filehandle(fh)
    vml._assemble_xml_file(1, 1024, None, [{'row': 1, 'col': 2, 'fillcolor': 'buttonFace    [67]', 'vertices': [2, 1, 0, 0, 3, 2, 0, 0, 128, 20, 64, 20], 'font': {'caption': 'Button    1'}, 'macro': '[0]!Button1_Click'}])
    exp = _vml_to_list('\n                                                                <xml    xmlns:v="urn:schemas-microsoft-com:vml"    xmlns:o="urn:schemas-microsoft-com:office:office"    xmlns:x="urn:schemas-microsoft-com:office:excel">\n                                                                        <o:shapelayout    v:ext="edit">\n                                                                                <o:idmap    v:ext="edit"    data="1"/>\n                                                                        </o:shapelayout>\n                                                                        <v:shapetype    id="_x0000_t201"    coordsize="21600,21600"    o:spt="201"    path="m,l,21600r21600,l21600,xe">\n                                                                                <v:stroke    joinstyle="miter"/>\n                                                                                <v:path    shadowok="f"    o:extrusionok="f"    strokeok="f"    fillok="f"    o:connecttype="rect"/>\n                                                                                <o:lock    v:ext="edit"    shapetype="t"/>\n                                                                        </v:shapetype>\n                                                                        <v:shape    id="_x0000_s1025"    type="#_x0000_t201"    style="position:absolute;margin-left:96pt;margin-top:15pt;width:48pt;height:15pt;z-index:1;mso-wrap-style:tight"    o:button="t"    fillcolor="buttonFace    [67]"    strokecolor="windowText    [64]"    o:insetmode="auto">\n                                                                                <v:fill    color2="buttonFace    [67]"    o:detectmouseclick="t"/>\n                                                                                <o:lock    v:ext="edit"    rotation="t"/>\n                                                                                <v:textbox    style="mso-direction-alt:auto"    o:singleclick="f">\n                                                                                        <div    style="text-align:center">\n                                                                                                <font    face="Calibri"    size="220"    color="#000000">Button    1</font>\n                                                                                        </div>\n                                                                                </v:textbox>\n                                                                                <x:ClientData    ObjectType="Button">\n                                                                                        <x:Anchor>2,    0,    1,    0,    3,    0,    2,    0</x:Anchor>\n                                                                                        <x:PrintObject>False</x:PrintObject>\n                                                                                        <x:AutoFill>False</x:AutoFill>\n                                                                                        <x:FmlaMacro>[0]!Button1_Click</x:FmlaMacro>\n                                                                                        <x:TextHAlign>Center</x:TextHAlign>\n                                                                                        <x:TextVAlign>Center</x:TextVAlign>\n                                                                                </x:ClientData>\n                                                                        </v:shape>\n                                                                </xml>\n                                                                ')
    got = _xml_to_list(fh.getvalue())
    self.assertEqual(got, exp)
