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());
fifo.enqueue("D");
assertEquals("A,B,C,D,", fifo.dump());
fifo.enqueue("E");
assertEquals("A,B,C,D,E", fifo.dump());
fifo.enqueue("F");