'Test the _write_auto_filter() method'

def test_write_auto_filter_20(self):

    matches = ['East', 'North']
    exp = '<autoFilter    ref="A1:D51"><filterColumn    colId="0"><filters><filter    val="East"/><filter    val="North"/></filters></filterColumn></autoFilter>'
    self.worksheet.filter_column_list('A', matches)
    self.worksheet._write_auto_filter()
    got = self.fh.getvalue()
    self.assertEqual(got, exp)
