private final ForwardingWrapperTester tester = new ForwardingWrapperTester();

  public void testGoodForwarder() {
    tester.testForwarding(Arithmetic.class, ForwardingArithmetic::new);
    tester.testForwarding(ParameterTypesDifferent.class, ParameterTypesDifferentForwarder::new);
  }

  public void testVoidMethodForwarding() {
    tester.testForwarding(Runnable.class, ForwardingRunnable::new);
  }

    private final transient ClassSanityTester tester;

    SerializableDummyProxy(ClassSanityTester tester) {
      this.tester = tester;
    }

    @Override
    <R> R dummyReturnValue(TypeToken<R> returnType) {
      return tester.getDummyValue(returnType);
    }

    @Override
    public boolean equals(@Nullable Object obj) {

  protected final <T> void setDefault(Class<T> type, T value) {
    tester.setDefault(type, value);
  }

  /**
   * Sets two distinct values for {@code type}. These values can be used for both null pointer
   * testing and equals testing.
   *
   * @since 17.0
   */
  protected final <T> void setDistinctValues(Class<T> type, T value1, T value2) {
    tester.setDistinctValues(type, value1, value2);
  }

  protected final <T> void setDefault(Class<T> type, T value) {
    tester.setDefault(type, value);
  }

  /**
   * Sets two distinct values for {@code type}. These values can be used for both null pointer
   * testing and equals testing.
   *
   * @since 17.0
   */
  protected final <T> void setDistinctValues(Class<T> type, T value1, T value2) {
    tester.setDistinctValues(type, value1, value2);
  }

import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tester for {@code Spliterator} implementations.
 *
 * @since 33.4.0 (but since 21.0 in the JRE flavor)
 */
@GwtCompatible
@NullMarked
@IgnoreJRERequirement // Users will use this only if they're already using Spliterator.

import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tester for {@code Spliterator} implementations.
 *
 * @since 21.0 (but only since 33.4.0 in the Android flavor)
 */
@GwtCompatible
@NullMarked
public final class SpliteratorTester<E extends @Nullable Object> {