@CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testRemove_present() {
    getSet().remove(e0());
    assertFalse(
        "After remove(present) a set should not contain the removed element.",
        getSet().contains(e0()));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedPresent() {
    assertFalse("add(present) should return false", getSet().add(e0()));
    expectUnchanged();
  }

  @CollectionFeature.Require(value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedNullPresent() {

        // These tests verify the PingResponse class structure is correct
        assertTrue(true);
    }

    public void test_getClusterName_returnsCorrectValue() {
        // Test cluster name getter exists
        FessConfig mockConfig = new FessConfig.SimpleImpl() {
            private static final long serialVersionUID = 1L;

            @Override
            public Set<String> getApiPingEsFieldSet() {

      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,
        getSet().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testHashCode_containingNull() {

  private List<E> values;
  private E a;
  private E b;
  private E c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    navigableSet = (NavigableSet<E>) getSet();
    values =
        copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));
    sort(values, navigableSet.comparator());

    }

    @Override
    public final Method getReadMethod() {
        return readMethod;
    }

    /**
     * Sets the getter method.
     *
     * @param readMethod
     *            The getter method.
     */
    protected final void setReadMethod(final Method readMethod) {
        this.readMethod = readMethod;
        if (readMethod != null) {

   * collection in setUp(), but that caused problems when a tester changed the
   * value of set or collection but not both.
   */
  protected final Set<E> getSet() {
    return (Set<E>) collection;
  }

  private List<E> values;
  private @Nullable E a;
  private @Nullable E b;
  private @Nullable E c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    sortedSet = (SortedSet<E>) getSet();
    values =
        copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));
    sort(values, sortedSet.comparator());

   * collection in setUp(), but that caused problems when a tester changed the
   * value of set or collection but not both.
   */
  protected final Set<E> getSet() {
    return (Set<E>) collection;
  }

  private List<E> values;
  private E a;
  private E b;
  private E c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    navigableSet = (NavigableSet<E>) getSet();
    values =
        copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));
    sort(values, navigableSet.comparator());