@SuppressWarnings("unused")
  @Test(expected = IllegalStateException.class)
  public void testColocateLowLatencyRegions() throws Exception {
    assumeTrue(isMainRun());

    // ensure colocating two low latency regions doesn't break lowLatancy
    // and colocating is achieved.

    Topology t = newTopology("testColocateLowLatencyRegions");
    Tester tester = t.getTester();
    // getConfig().put(ContextProperties.KEEP_ARTIFACTS, true);

    TStream<String> s1 =
        t.strings("a").lowLatency().modify(getContainerIdAppend()).modify(getContainerIdAppend());
    s1.endLowLatency();

    TStream<String> s2 =
        t.strings("A").lowLatency().modify(getContainerIdAppend()).modify(getContainerIdAppend());
    s2.endLowLatency();

    s1.colocate(s2); // expect throw ISE: colocate in a low latency region

    // once it's supported... (today it breaks the low latency guarantee)
    // and adjust isMainRun() too
    //        // Given the default fuse-island behavior, expect islands to continue
    //        // to be fused, now both in a single container.
    //
    //        // Today FAILING in an interesting way.
    //        // There are 2 PEs:
    //        // - one has just the single colocated s1 and s2 modify ops
    //        // - the other has everything else
    //
    //        TStream<String> all = s1.union(s2);
    //        all.print();
    //        Condition<Long> nTuples = tester.tupleCount(all.filter(new AllowAll<String>()), 2);
    //        Condition<List<String>> contents = tester.stringContents(
    //                all.filter(new AllowAll<String>()), "");
    //
    //        complete(tester, nTuples, 10, TimeUnit.SECONDS);
    //
    //        Set<String> ids = getContainerIds(contents.getResult());
    //        assertEquals("ids: "+ids, 1, ids.size());
  }