public void testCloning() {
        BlockContainer c1 = new BlockContainer(new FlowArrangement());
        c1.add(new EmptyBlock(1.2, 3.4));
        
        BlockContainer c2 = null;
        
        try {
            c2 = (BlockContainer) c1.clone();
        }
        catch (CloneNotSupportedException e) {
            System.err.println("Failed to clone.");
        }
        assertTrue(c1 != c2);
        assertTrue(c1.getClass() == c2.getClass());
        assertTrue(c1.equals(c2));