@Test
  public void stringableList() throws Exception {
    // Empty list case
    MRCompactor.StringableList ls = new MRCompactor.StringableList();
    String s = ls.toString();
    Assert.assertEquals("0:", s);
    ls = new MRCompactor.StringableList(s);
    Assert.assertEquals(0, ls.size());

    ls = new MRCompactor.StringableList();
    ls.add(new Path("/tmp"));
    ls.add(new Path("/usr"));
    s = ls.toString();
    Assert.assertTrue("Expected 2:4:/tmp4:/usr or 2:4:/usr4:/tmp, got " + s,
        "2:4:/tmp4:/usr".equals(s) || "2:4:/usr4:/tmp".equals(s));
    ls = new MRCompactor.StringableList(s);
    Assert.assertEquals(2, ls.size());
    boolean sawTmp = false, sawUsr = false;
    for (Path p : ls) {
      if ("/tmp".equals(p.toString())) sawTmp = true;
      else if ("/usr".equals(p.toString())) sawUsr = true;
      else Assert.fail("Unexpected path " + p.toString());
    }
    Assert.assertTrue(sawTmp);
    Assert.assertTrue(sawUsr);
  }
Tests for the worker thread and its MR jobs.
todo: most delta files in this test suite use txn id range, i.e. [N,N+M]
That means that they all look like they were created by compaction or by streaming api.
Delta files created by SQL should have [N,N] range (and a suffix in v1.3 and later)
Need to change some of these to have better test coverage.
ql/src/test/org/apache/hadoop/hive/ql/txn/compactor/TestWorker.java