@Test
    public final void testIterator() {
        Iterator<SpatialTree<Sphere>> it;
        SpatialTree<Sphere> tree = new SpatialTree<Sphere>(objects);
        int count = 0;

        it = tree.leafInterator();

        while (it.hasNext()) {
            for (Sphere s : it.next()) {
                assertTrue(s instanceof Sphere);
                count++;
            }
        }

        assertEquals(objects.size(), count);
    }