### Question:
BackgroundModel extends Observable { public void remove(Collection<TileGeometry> geometry) { for (TileGeometry aGeometry : geometry) { myGeometries.remove(aGeometry); } setChanged(); notifyObservers(GEOMETRIES_PROP); }  void add(Collection<TileGeometry> geometry); Collection<TileGeometry> getGeometries(); List<Double> getGeometryScaleFactors(); void remove(Collection<TileGeometry> geometry); static final String GEOMETRIES_PROP; }### Answer:
@Test public void testRemove() { EasyMockSupport support = new EasyMockSupport(); BackgroundModel model = new BackgroundModel(); Observer observer = createObserver(support, model); TileGeometry[] geometries = createGeometries(); model.add(New.list(geometries)); support.replayAll(); model.addObserver(observer); model.remove(New.list(geometries[0])); assertEquals(1, model.getGeometries().size()); assertEquals(geometries[1], model.getGeometries().iterator().next()); support.verifyAll(); }