def METHOD_NAME(self, widget, mocker):
    """ Assure help file is shown """
    widget.manager = QtWidgets.QWidget()
    mocker.patch.object(widget.manager, 'showHelp', create=True)
    widget.displayHelp()
    assert widget.manager.showHelp.called_once()
    args = widget.manager.showHelp.call_args
    assert 'sld_calculator_help.html' in args[0][0]