UberfireColumnPicker { protected void showColumnPickerPopup(final int left, final int top) { VerticalPanel popupContent = GWT.create(VerticalPanel.class); initCheckBoxs(popupContent); addResetButtom(left, top, popupContent); configureColorPickerPopup(left, top, popupContent); } UberfireColumnPicker(DataGrid<T> dataGrid); void addColumnChangedHandler(ColumnChangedHandler handler); Collection<ColumnMeta<T>> getColumnMetaList(); void columnMoved(final int visibleFromIndex,
                            final int visibleBeforeIndex); void addColumn(ColumnMeta<T> columnMeta); void adjustColumnWidths(); void addColumns(List<ColumnMeta<T>> columnMetas); void removeColumn(ColumnMeta<T> columnMeta); Button createToggleButton(); int getDataGridMinWidth(); void setDefaultColumnWidthSize(int defaultColumSize);  }
@Test public void testOnlyAddHeaderStringColumnPickerPopup() { uberfireColumnPicker.showColumnPickerPopup(0, 0); verify(popupContent, times(2)).add(any(Widget.class)); }