Nodeid[] nodes2 = { allRevs[0], allRevs[1], allRevs[2] };
RevisionSet fromR3 = complete.subtract(new RevisionSet(nodes2));
Nodeid[] nodes3 = { allRevs[2], allRevs[3] };
errorCollector.assertEquals(new RevisionSet(nodes3), fromR2.roots(parentHelper));
Nodeid[] nodes4 = { allRevs[3], allRevs[4], allRevs[5] };
errorCollector.assertEquals(new RevisionSet(nodes4), fromR3.roots(parentHelper));
Nodeid[] nodes5 = { allRevs[9], allRevs[7] };
// heads
errorCollector.assertEquals(new RevisionSet(nodes5), complete.heads(parentHelper));
Nodeid[] nodes6 = { allRevs[9], allRevs[8] };
RevisionSet toR7 = complete.subtract(new RevisionSet(nodes6));