git.add().addFilepattern("a.txt").call();
RevCommit c = git.commit().setMessage("initial commit").call();
// when
TreeWalk walk = new TreeWalk(db);
walk.addTree(new EmptyTreeIterator());
walk.addTree(c.getTree());
walk.addTree(new EmptyTreeIterator());
List<ThreeWayDiffEntry> result = ThreeWayDiffEntry.scan(walk);
// then
assertThat(result, notNullValue());
assertThat(Integer.valueOf(result.size()), is(Integer.valueOf(1)));