@Test public void recBuffer07() {

    RecordBuffer rb = make(4,5);
    contains(rb, 2, 4, 6, 8);
    rb.shiftUp(3);
    rb.set(3, r(1));
    contains(rb, 2, 4, 6, 1, 8);
    rb.shiftDown(3);
    contains(rb, 2, 4, 6, 8);
}