new EqualsTester()
        .addEqualityGroup(f, Functions.constant("correct"))
        .addEqualityGroup(Functions.constant("incorrect"))
        .addEqualityGroup(Functions.toStringFunction())
        .addEqualityGroup(g)
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(g, Functions.<@Nullable Object>constant(null))
        .addEqualityGroup(Functions.constant("incorrect"))

    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();

    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();

    new EqualsTester()
        .addEqualityGroup(f, Functions.constant("correct"))
        .addEqualityGroup(Functions.constant("incorrect"))
        .addEqualityGroup(Functions.toStringFunction())
        .addEqualityGroup(g)
        .testEquals();

    new EqualsTester()
        .addEqualityGroup(g, Functions.<@Nullable Object>constant(null))
        .addEqualityGroup(Functions.constant("incorrect"))

    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();

    @CanIgnoreReturnValue
    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();

    new EqualsTester()
        .addEqualityGroup(Range.all())
        .addEqualityGroup(Range.atLeast(1), Range.downTo(1, CLOSED))
        .addEqualityGroup(Range.greaterThan(1), Range.downTo(1, OPEN))
        .addEqualityGroup(Range.atMost(7), Range.upTo(7, CLOSED))
        .addEqualityGroup(Range.lessThan(7), Range.upTo(7, OPEN))
        .addEqualityGroup(Range.open(1, 7), Range.range(1, OPEN, 7, OPEN))

    new EqualsTester()
        .addEqualityGroup(A.constructor(), A.constructor())
        .addEqualityGroup(A.method("privateMethod"), A.method("privateMethod"))
        .addEqualityGroup(A.method("publicFinalMethod"))
        .addEqualityGroup(Prepender.constructor(), Prepender.constructor())
        .addEqualityGroup(Prepender.constructor(String.class, int.class))