public void testEqualsSameContents() {
    new EqualsTester()
        .addEqualityGroup(
            getMultiset(), getSubjectGenerator().create(getSampleElements().toArray()))
        .testEquals();
  }

  @CollectionSize.Require(absent = ZERO)
  public void testNotEqualsEmpty() {
    new EqualsTester()
        .addEqualityGroup(getMultiset())
        .addEqualityGroup(getSubjectGenerator().create())
        .testEquals();
  }

 * that are equal to each other but unequal to the objects in any other group. For example:
 *
 * <pre>
 * new EqualsTester()
 *     .addEqualityGroup(new User("page"), new User("page"))
 *     .addEqualityGroup(new User("sergey"))
 *     .testEquals();
 * </pre>
 *
 * <p>This tests:
 *
 * <ul>
 *   <li>comparing each object against itself returns true
 *   <li>comparing each object against null returns false

  public void testWrap() {
    new EqualsTester()
        .addEqualityGroup(
            LENGTH_EQUIVALENCE.wrap("hello"),
            LENGTH_EQUIVALENCE.wrap("hello"),
            LENGTH_EQUIVALENCE.wrap("world"))
        .addEqualityGroup(LENGTH_EQUIVALENCE.wrap("hi"), LENGTH_EQUIVALENCE.wrap("yo"))
        .addEqualityGroup(
            LENGTH_EQUIVALENCE.<@Nullable String>wrap(null),

  public void testWrap() {
    new EqualsTester()
        .addEqualityGroup(
            LENGTH_EQUIVALENCE.wrap("hello"),
            LENGTH_EQUIVALENCE.wrap("hello"),
            LENGTH_EQUIVALENCE.wrap("world"))
        .addEqualityGroup(LENGTH_EQUIVALENCE.wrap("hi"), LENGTH_EQUIVALENCE.wrap("yo"))
        .addEqualityGroup(
            LENGTH_EQUIVALENCE.<@Nullable String>wrap(null),

    new EqualsTester()
        .addEqualityGroup(Funnels.byteArrayFunnel())
        .addEqualityGroup(Funnels.integerFunnel())
        .addEqualityGroup(Funnels.longFunnel())
        .addEqualityGroup(Funnels.unencodedCharsFunnel())
        .addEqualityGroup(Funnels.stringFunnel(UTF_8))
        .addEqualityGroup(Funnels.stringFunnel(US_ASCII))
        .addEqualityGroup(

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(newDelegatingList(LIST1))
        // Actually, this violates List#equals contract.
        // But whatever, no one is going to proxy List (hopefully).
        .addEqualityGroup(newDelegatingList(LIST1))
        .addEqualityGroup(newDelegatingList(LIST2))
        .addEqualityGroup(
            newProxyWithEqualsForInterfaces(List.class, Runnable.class),

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            RemovalNotification.create("one", 1, RemovalCause.EXPLICIT),
            RemovalNotification.create("one", 1, RemovalCause.REPLACED))
        .addEqualityGroup(RemovalNotification.create("1", 1, RemovalCause.EXPLICIT))
        .addEqualityGroup(RemovalNotification.create("one", 2, RemovalCause.EXPLICIT))
        .testEquals();
  }

    FreshValueGenerator generator = new FreshValueGenerator();
    T instance = generator.newFreshProxy(interfaceType);
    new EqualsTester()
        .addEqualityGroup(wrapperFunction.apply(instance), wrapperFunction.apply(instance))
        .addEqualityGroup(wrapperFunction.apply(generator.newFreshProxy(interfaceType)))
        // TODO: add an overload to EqualsTester to print custom error message?
        .testEquals();
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            RemovalNotification.create("one", 1, RemovalCause.EXPLICIT),
            RemovalNotification.create("one", 1, RemovalCause.REPLACED))
        .addEqualityGroup(RemovalNotification.create("1", 1, RemovalCause.EXPLICIT))
        .addEqualityGroup(RemovalNotification.create("one", 2, RemovalCause.EXPLICIT))
        .testEquals();
  }

  @CollectionFeature.Require(SERIALIZABLE)
  public void testReserializeMap() {
    Map<K, V> deserialized = SerializableTester.reserialize(getMap());
    new EqualsTester().addEqualityGroup(getMap(), deserialized).testEquals();
  }