}

  /**
   * {@inheritDoc}
   *
   * <p>This method returns a serializable {@code ImmutableSortedSet}.
   *
   * <p>The {@link SortedSet#subSet} documentation states that a subset of a subset throws an {@link
   * IllegalArgumentException} if passed a {@code fromElement} smaller than an earlier {@code
   * fromElement}. However, this method doesn't throw an exception in that situation, but instead

  public void testRetainAll_supersetUnsupported() {
    expectReturnsFalseOrThrows(superset);
    expectUnchanged();
  }

  // retainAll(subset)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testRetainAll_subset() {
    expectReturnsTrue(nonEmptyProperSubset);
    expectContents(nonEmptyProperSubset.toRetain);
  }

            3),
        rangeMap.asMapOfRanges());

    assertThrows(IllegalArgumentException.class, () -> sub.put(Range.open(9, 12), 5));

    RangeMap<Integer, Integer> subSub = sub.subRangeMap(Range.closedOpen(5, 5));
    subSub.put(Range.closedOpen(5, 5), 6); // should be a no-op
    assertEquals(
        ImmutableMap.of(
            Range.open(3, 7),
            1,
            Range.closed(7, 9),

  }

  public void testRowKeySetSubSet() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c', "dog", 2, 'd');
    Set<String> set = sortedTable.rowKeySet().subSet("cat", "egg");
    assertEquals(Collections.singleton("dog"), set);
    set.clear();
    assertTrue(set.isEmpty());
    assertEquals(ImmutableSet.of("bar", "foo"), sortedTable.rowKeySet());
  }

  }

  /**
   * Checks that the elements of the iterable are calculated on the fly. Concretely, that means that
   * {@link SuccessorsFunction#successors(Object)} can only be called for a subset of all nodes.
   */
  @Test
  public void forGraph_breadthFirstIterable_emptyGraph() {
    assertEqualCharNodes(
        Traverser.forGraph(createDirectedGraph()).breadthFirst(charactersOf("")), "");

      for (int j = i + 1; j <= 20; j++) {
        assertEquals(expectedSet.subSet(i, false, j, false), asSet.subSet(i, false, j, false));
        assertEquals(expectedSet.subSet(i, true, j, false), asSet.subSet(i, true, j, false));
        assertEquals(expectedSet.subSet(i, false, j, true), asSet.subSet(i, false, j, true));
        assertEquals(expectedSet.subSet(i, true, j, true), asSet.subSet(i, true, j, true));
      }
    }
  }

    }

    @Override
    public NavigableSet<K> subSet(
        @ParametricNullness K fromElement, @ParametricNullness K toElement) {
      return subSet(fromElement, true, toElement, false);
    }

    @Override
    public NavigableSet<K> subSet(
        @ParametricNullness K fromElement,
        boolean fromInclusive,

          }
          return elemItr.next();
        }
      };
    }

    ImmutableSortedSet<C> subSet(Range<C> range) {
      return subRangeSet(range).asSet(domain);
    }

    @Override
    ImmutableSortedSet<C> headSetImpl(C toElement, boolean inclusive) {
      return subSet(Range.upTo(toElement, BoundType.forBoolean(inclusive)));
    }

    @Override
    ImmutableSortedSet<C> subSetImpl(

          }
          return elemItr.next();
        }
      };
    }

    ImmutableSortedSet<C> subSet(Range<C> range) {
      return subRangeSet(range).asSet(domain);
    }

    @Override
    ImmutableSortedSet<C> headSetImpl(C toElement, boolean inclusive) {
      return subSet(Range.upTo(toElement, BoundType.forBoolean(inclusive)));
    }

    @Override
    ImmutableSortedSet<C> subSetImpl(

      for (int j = i + 1; j <= 20; j++) {
        assertEquals(expectedSet.subSet(i, false, j, false), asSet.subSet(i, false, j, false));
        assertEquals(expectedSet.subSet(i, true, j, false), asSet.subSet(i, true, j, false));
        assertEquals(expectedSet.subSet(i, false, j, true), asSet.subSet(i, false, j, true));
        assertEquals(expectedSet.subSet(i, true, j, true), asSet.subSet(i, true, j, true));
      }
    }
  }