// make them visible
comp.add(r1, new Revision(0x01, 0, 0));
comp.add(r2, new Revision(0x02, 0, 0));
comp.purge(0x01);
// null indicates older than earliest range
assertNull(comp.getRevisionSeen(r1));
// r2 is still seen at 0x02
assertEquals(new Revision(0x02, 0, 0), comp.getRevisionSeen(r2));