@Test public void recBuffer05() {

    RecordBuffer rb = make(4,5);
    contains(rb, 2, 4, 6, 8);
    rb.shiftUp(2);
    rb.set(2, r(0));
    contains(rb, 2, 4, 0, 6, 8);
    rb.shiftDown(2);
    contains(rb, 2, 4, 6, 8);
}