/** Performs an atomic compare-and-set of {@link AggregateFutureState#seenExceptionsField}. */
    abstract void compareAndSetSeenExceptions(
        AggregateFutureState<?> state, @Nullable Set<Throwable> expect, Set<Throwable> update);

    /** Performs an atomic decrement-and-get of {@link AggregateFutureState#remainingField}. */
    abstract int decrementAndGetRemainingCount(AggregateFutureState<?> state);

package com.google.common.util.concurrent;

import static com.google.common.collect.Sets.newHashSet;

import java.util.Set;
import org.jspecify.annotations.Nullable;

/** Emulation of AggregateFutureState. */
abstract class AggregateFutureState<OutputT extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<OutputT> {
  // Lazily initialized the first time we see an exception; not released until all the input futures

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;

import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests that {@link AggregateFutureState} uses the expected {@code AtomicHelper} implementation.
 *
 * <p>We have more thorough testing of {@code AtomicHelper} implementations in {@link

/**
 * Tests our AtomicHelper fallback strategy in AggregateFutureState.
 *
 * <p>On different platforms AggregateFutureState uses different strategies for its core
 * synchronization primitives. The strategies are all implemented as subtypes of AtomicHelper and
 * the strategy is selected in the static initializer of AggregateFutureState. This is convenient

     *
     * SynchronizedHelper also ends up getting used under the JVM during
     * AggregateFutureStateFallbackAtomicHelperTest, as discussed in a comment in
     * AggregateFutureState.
     *
     * Here, we check that we're able to force AbstractFutureState to select SynchronizedHelper, and
     * below, we actually run the AbstractFutureTest methods under that scenario.
     */