assertThrows(
        NullPointerException.class,
        () -> equalsTester.addEqualityGroup(reference, (Object[]) null));
  }

  /**
   * Test adding objects only by addEqualityGroup, with no reference object specified in the
   * constructor.
   */
  public void testAddEqualObjectWithOArgConstructor() {
    equalsTester.addEqualityGroup(equalObject1, notEqualObject1);
    try {
      equalsTester.testEquals();

    assertThrows(
        NullPointerException.class,
        () -> equalsTester.addEqualityGroup(reference, (Object[]) null));
  }

  /**
   * Test adding objects only by addEqualityGroup, with no reference object specified in the
   * constructor.
   */
  public void testAddEqualObjectWithOArgConstructor() {
    equalsTester.addEqualityGroup(equalObject1, notEqualObject1);
    try {
      equalsTester.testEquals();

        .addEqualityGroup(parse("expireAfterWrite=60m"), parse("expireAfterWrite=1h"))
        .addEqualityGroup(parse("weakKeys"), parse("weakKeys"))
        .addEqualityGroup(parse("softValues"), parse("softValues"))
        .addEqualityGroup(parse("weakValues"), parse("weakValues"))
        .addEqualityGroup(parse("recordStats"), parse("recordStats"))
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(FALSE, Predicates.alwaysFalse())
        .addEqualityGroup(TRUE)
        .addEqualityGroup(Predicates.not(FALSE))
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(Predicates.isNull(), Predicates.isNull())
        .addEqualityGroup(Predicates.notNull())
        .addEqualityGroup(Predicates.not(Predicates.isNull()))
        .testEquals();

    private final EqualsTester tester = new EqualsTester();

    TypeVariableEqualsTester addEqualityGroup(Type jvmType, Type... types) {
      if (Types.NativeTypeVariableEquals.NATIVE_TYPE_VARIABLE_ONLY) {
        tester.addEqualityGroup(jvmType);
        tester.addEqualityGroup((Object[]) types);
      } else {
        tester.addEqualityGroup(Lists.asList(jvmType, types).toArray());
      }
      return this;
    }

    private final EqualsTester tester = new EqualsTester();

    TypeVariableEqualsTester addEqualityGroup(Type jvmType, Type... types) {
      if (Types.NativeTypeVariableEquals.NATIVE_TYPE_VARIABLE_ONLY) {
        tester.addEqualityGroup(jvmType);
        tester.addEqualityGroup((Object[]) types);
      } else {
        tester.addEqualityGroup(Lists.asList(jvmType, types).toArray());
      }
      return this;
    }

        .addEqualityGroup(parse("expireAfterWrite=60m"), parse("expireAfterWrite=1h"))
        .addEqualityGroup(parse("weakKeys"), parse("weakKeys"))
        .addEqualityGroup(parse("softValues"), parse("softValues"))
        .addEqualityGroup(parse("weakValues"), parse("weakValues"))
        .addEqualityGroup(parse("recordStats"), parse("recordStats"))
        .testEquals();

        .addEqualityGroup(
            new PairedStats(OTHER_MANY_VALUES_STATS, MANY_VALUES_STATS_ITERABLE, 1.23))
        .addEqualityGroup(
            new PairedStats(MANY_VALUES_STATS_ITERABLE, MANY_VALUES_STATS_ITERABLE, 1.23))
        .addEqualityGroup(new PairedStats(TWO_VALUES_STATS, MANY_VALUES_STATS_ITERABLE, 1.23))
        .addEqualityGroup(new PairedStats(MANY_VALUES_STATS_ITERABLE, ONE_VALUE_STATS, 1.23))

        assertThrows(IncomparableValueException.class, () -> c.compare(5, 666));
    assertEquals(666, expected.value);
    new EqualsTester()
        .addEqualityGroup(c, Ordering.explicit(42, 5))
        .addEqualityGroup(Ordering.explicit(5, 42))
        .addEqualityGroup(Ordering.explicit(42))
        .testEquals();
    reserializeAndAssert(c);
  }

  public void testExplicit_sortingExample() {

        assertThrows(IncomparableValueException.class, () -> c.compare(5, 666));
    assertEquals(666, expected.value);
    new EqualsTester()
        .addEqualityGroup(c, Ordering.explicit(42, 5))
        .addEqualityGroup(Ordering.explicit(5, 42))
        .addEqualityGroup(Ordering.explicit(42))
        .testEquals();
    reserializeAndAssert(c);
  }

  public void testExplicit_sortingExample() {