'L{_SourceLineElement} renders a source line and line number.'

def test_sourceLineElement(self):

    element = _SourceLineElement(TagLoader(tags.div(tags.span(render='lineNumber'), tags.span(render='sourceLine'))), 50, "                print    'hello'")
    d = flattenString(None, element)
    expected = u"<div><span>50</span><span>    \xa0    \xa0print    'hello'</span></div>"
    d.addCallback(self.assertEqual, expected.encode('utf-8'))
    return d
