### Question:
DMNGridLayerControlImpl extends AbstractCanvasControl<AbstractCanvas> implements DMNGridLayerControl { @Override protected void doDestroy() { withCanvasHandler(abstractCanvasHandler -> { abstractCanvasHandler.removeRegistrationListener(redrawElementListener); abstractCanvasHandler.removeDomainObjectListener(redrawDomainObjectListener); }); session = Optional.empty(); gridLayer = null; } DMNGridLayerControlImpl(); @Override void bind(final ClientSession session); @Override DMNGridLayer getGridLayer();  }### Answer:
@Test public void testDoDestroy() { control.doDestroy(); assertNull(control.getGridLayer()); }