ImmutableSortedSet.Builder<String> zis =
        ImmutableSortedSet.<String>naturalOrder().add("c", "b", "c");
    ImmutableSortedSet.Builder<String> zat =
        ImmutableSortedSet.<String>naturalOrder().add("a", "b", "d", "c");
    ImmutableSortedSet<String> sortedSet = zis.combine(zat).build();
    assertThat(sortedSet).containsExactly("a", "b", "c", "d").inOrder();
  }

    ImmutableMap.Builder<String, Integer> zis =
        ImmutableMap.<String, Integer>builder().put("one", 1);
    ImmutableMap.Builder<String, Integer> zat =
        ImmutableMap.<String, Integer>builder().put("two", 2).put("three", 3);
    assertMapEquals(zis.combine(zat).build(), "one", 1, "two", 2, "three", 3);
  }

  // TODO(b/172823566): Use mainline testToImmutableMap once CollectorTester is usable to java7.

  public void testToImmutableSet_java7() {
    ImmutableSet.Builder<String> zis = ImmutableSet.<String>builder().add("a", "b", "a");
    ImmutableSet.Builder<String> zat = ImmutableSet.<String>builder().add("c", "b", "d", "c");
    ImmutableSet<String> set = zis.combine(zat).build();
    assertThat(set).containsExactly("a", "b", "c", "d").inOrder();
  }

  @Override
  <E extends Comparable<E>> Builder<E> builder() {

        ImmutableSetMultimap.<String, Integer>builder().put("a", 1).put("b", 2);
    ImmutableSetMultimap.Builder<String, Integer> zat =
        ImmutableSetMultimap.<String, Integer>builder().put("a", 3).put("c", 4);
    ImmutableSetMultimap<String, Integer> multimap = zis.combine(zat).build();
    assertThat(multimap.keySet()).containsExactly("a", "b", "c").inOrder();

    ImmutableRangeSet.Builder<Integer> zis =
        ImmutableRangeSet.<Integer>builder().add(rangeOne).add(rangeTwo);
    ImmutableRangeSet.Builder<Integer> zat =
        ImmutableRangeSet.<Integer>builder().add(rangeThree).add(rangeFour);

    ImmutableRangeSet<Integer> rangeSet = zis.combine(zat).build();

    assertThat(rangeSet.asRanges())
        .containsExactly(Range.closedOpen(1, 3), Range.closedOpen(4, 5), Range.closedOpen(6, 9))

        ImmutableListMultimap.<String, Integer>builder().put("a", 1).put("b", 2);
    ImmutableListMultimap.Builder<String, Integer> zat =
        ImmutableListMultimap.<String, Integer>builder().put("a", 3).put("c", 4);
    ImmutableListMultimap<String, Integer> multimap = zis.combine(zat).build();
    assertThat(multimap.keySet()).containsExactly("a", "b", "c").inOrder();

  public void testToImmutableList_java7_combine() {
    ImmutableList.Builder<String> zis = ImmutableList.<String>builder().add("a", "b");
    ImmutableList.Builder<String> zat = ImmutableList.<String>builder().add("c", "d");
    ImmutableList<String> list = zis.combine(zat).build();
    assertEquals(asList("a", "b", "c", "d"), list);
  }

  // Basic tests

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester