### Question:
ExpressionGridCacheImpl extends AbstractCanvasControl<AbstractCanvas> implements ExpressionGridCache { @Override protected void doDestroy() { cache.clear(); } ExpressionGridCacheImpl(); @Override Optional<BaseExpressionGrid<? extends Expression, ? extends GridData, ? extends BaseUIModelMapper>> getExpressionGrid(final String nodeUUID); @Override void putExpressionGrid(final String nodeUUID,
                                  final Optional<BaseExpressionGrid<? extends Expression, ? extends GridData, ? extends BaseUIModelMapper>> gridWidget); @Override void removeExpressionGrid(final String nodeUUID);  }### Answer:
@Test public void testDoDestroy() { when(editor.isCacheable()).thenReturn(true); cache.putExpressionGrid(UUID, Optional.of(editor)); assertThat(cache.getContent()).isNotEmpty(); cache.doDestroy(); assertThat(cache.getContent()).isEmpty(); }