.containsExactly(Range.lessThan(3), Range.greaterThan(3))
        .inOrder();
  }

  public void testRemoveMiddle() {
    TreeRangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.atMost(6));
    rangeSet.remove(Range.closedOpen(3, 4));
    testInvariants(rangeSet);
    assertThat(rangeSet.asRanges())
        .containsExactly(Range.lessThan(3), Range.closed(4, 6))
        .inOrder();

    assertEquals(empty, Maps.subMap(map, Range.lessThan(0)));
    assertEquals(ImmutableSortedMap.of(2, 0), Maps.subMap(map, Range.lessThan(4)));
    assertEquals(ImmutableSortedMap.of(2, 0, 4, 0, 6, 0), Maps.subMap(map, Range.lessThan(7)));
    assertEquals(map, Maps.subMap(map, Range.lessThan(20)));

    assertEquals(empty, Maps.subMap(map, Range.atMost(0)));

    assertEquals(empty, Maps.subMap(map, Range.lessThan(0)));
    assertEquals(ImmutableSortedMap.of(2, 0), Maps.subMap(map, Range.lessThan(4)));
    assertEquals(ImmutableSortedMap.of(2, 0, 4, 0, 6, 0), Maps.subMap(map, Range.lessThan(7)));
    assertEquals(map, Maps.subMap(map, Range.lessThan(20)));

    assertEquals(empty, Maps.subMap(map, Range.atMost(0)));

}

TF_Operation* Neg(TF_Operation* n, TF_Graph* graph, TF_Status* s,
                  const char* name) {
  TF_Operation* op;
  NegHelper(n, graph, s, name, &op);
  return op;
}

TF_Operation* LessThan(TF_Output l, TF_Output r, TF_Graph* graph,
                       TF_Status* s) {
  TF_OperationDescription* desc = TF_NewOperation(graph, "Less", "less_than");
  TF_AddInput(desc, l);
  TF_AddInput(desc, r);

    // Initialize outputs so we can easily detect errors/bugs
    outputs.resize(2, {nullptr, -1});

    // Create loop: while (input1 < input2) input1 += input2 + 1
    TF_Operation* less_than = LessThan(
        params->cond_inputs[0], params->cond_inputs[1], params->cond_graph, s_);
    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
    params->cond_output = {less_than, 0};