RingFifo fifo = new RingFifo(5);
assertEquals(",,,,", fifo.dump());
fifo.enqueue("A");
assertEquals("A", fifo.peek());
assertEquals("A,,,,", fifo.dump());
fifo.enqueue("B");
assertEquals("A,B,,,", fifo.dump());
fifo.enqueue("C");
assertEquals("A,B,C,,", fifo.dump());