### Question:
DMNGridWidgetDnDMouseUpHandler extends GridWidgetDnDMouseUpHandler { @Override public void onNodeMouseUp(final NodeMouseUpEvent event) { if (state.getOperation() == GridWidgetDnDHandlersState.GridWidgetHandlersOperation.COLUMN_RESIZE) { final GridWidget gridWidget = state.getActiveGridWidget(); final List<GridColumn<?>> gridColumns = state.getActiveGridColumns(); if (isBaseGrid(gridWidget) && isSingleDMNColumn(gridColumns)) { final BaseGrid uiGridWidget = (BaseGrid) gridWidget; final DMNGridColumn uiColumn = (DMNGridColumn) gridColumns.get(0); uiGridWidget.registerColumnResizeCompleted(uiColumn, state.getEventInitialColumnWidth()); } } super.onNodeMouseUp(event); } DMNGridWidgetDnDMouseUpHandler(final GridLayer layer,
                                          final GridWidgetDnDHandlersState state); @Override void onNodeMouseUp(final NodeMouseUpEvent event);  }### Answer:
@Test public void testColumnResize() { state.setOperation(GridWidgetHandlersOperation.COLUMN_RESIZE); state.setActiveGridWidget(activeGridWidget); state.setActiveGridColumns(Collections.singletonList(activeGridColumn)); state.setEventInitialColumnWidth(INITIAL_WIDTH); handler.onNodeMouseUp(event); verify(activeGridWidget).registerColumnResizeCompleted(activeGridColumn, INITIAL_WIDTH); }