@Test
  public void intersectInto() {
    MutableSet<String> set =
        MultiReaderUnifiedSet.newSetWith("1", "2", "3", "4").asReadUntouchable();
    MutableSet<String> intersect =
        set.intersectInto(UnifiedSet.newSetWith("a", "b", "c", "1"), UnifiedSet.<String>newSet());
    Verify.assertSize(1, intersect);
    Assert.assertEquals(UnifiedSet.newSetWith("1"), intersect);

    Verify.assertEmpty(
        set.intersectInto(UnifiedSet.newSetWith("not present"), UnifiedSet.<String>newSet()));
  }