ComponentCellKeyExtension extends Grid.AbstractGridExtension { public static ComponentCellKeyExtension extend(Grid grid) { return new ComponentCellKeyExtension(grid); } private  ComponentCellKeyExtension(final Grid grid); static ComponentCellKeyExtension extend(Grid grid);  }
@Test public void testExtend() throws Exception { Grid grid = new Grid(); assertFalse(containsComponentCellKeyExtension(grid)); ComponentCellKeyExtension.extend(grid); assertTrue(containsComponentCellKeyExtension(grid)); }