}

  private static class StringWrapper {
    private final String value;

    StringWrapper(String value) {
      this.value = value;
    }
  }

  @GwtIncompatible // J2CL generics problem
  public void testAndThen() {
    Converter<StringWrapper, String> first =
        new Converter<StringWrapper, String>() {
          @Override
          protected String doForward(StringWrapper object) {

   * probably work around it by changing how we annotate the J2CL EnumMap, but that's probably more
   * trouble than just using Object.class.)
   *
   * Then we declare the getters for these fields as @GwtIncompatible so that no one can try to use
   * them under J2CL—or, as an unfortunate side effect, under GWT. We do still give the fields

  @J2ktIncompatible
  @GwtIncompatible // not used under GWT, and super.getName() is not available under J2CL
  public final String getTestMethodName() {
    return super.getName();
  }

  @J2ktIncompatible
  @GwtIncompatible // not used under GWT, and super.getName() is not available under J2CL
  @Override
  public String getName() {
    return super.getName() + '[' + suiteName + ']';
  }

  /**

        .then(onFulfilled, onRejected);
  }
}

/**
 * Subset of the elemental2 IThenable interface without the single-parameter overload, which allows
 * us to implement it using a default implementation in J2cl ListenableFuture.
 */
@JsType(isNative = true, namespace = JsPackage.GLOBAL, name = "IThenable")
interface IThenable<T extends @Nullable Object> {
  <V extends @Nullable Object> IThenable<V> then(

    return result;
  }

  /*
   * If I understand correctly:
   *
   * This needs to be a @JsMethod so that J2CL knows to look for a JavaScript implemention of
   * it in Platform.native.js. (The JavaScript implementation inline below is visible to *GWT*, but
   * *J2CL* doesn't look at it.)
   *
   * However, once it's a @JsMethod, GWT produces a warning. That's because (a) the *other* purpose

import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible
@NullMarked
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {

import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible
@NullMarked
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {

public final class MoreCollectors {

  /*
   * TODO(lowasser): figure out if we can convert this to a concurrent AtomicReference-based
   * collector without breaking j2cl?
   */
  private static final Collector<Object, ?, Optional<Object>> TO_OPTIONAL =
      Collector.of(
          ToOptionalState::new,
          ToOptionalState::add,
          ToOptionalState::combine,

import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible
@NullMarked
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {

  static void interruptCurrentThread() {}

  static void rethrowIfErrorOtherThanStackOverflow(Throwable t) {
    if (t instanceof Error) {
      // There is no StackOverflowError under GWT/J2CL.
      throw (Error) t;
    }
  }

  static <V extends @Nullable Object> V get(AbstractFuture<V> future)
      throws InterruptedException, ExecutionException {
    return future.getFromAlreadyDoneTrustedFuture();