import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Basher test for {@link ConcurrentHashMultiset}: start a bunch of threads, have each of them do
 * operations at random. Each thread keeps track of the per-key deltas that it's directly
 * responsible for; after all threads have completed, we sum the per-key deltas and compare to the

How to contribute
=================

Thank you so much for wanting to contribute to Guava! Here are a few important
things you should know about contributing:

1.  API changes require discussion, use cases, etc. Code comes later.
2.  Pull requests are great for small fixes for bugs, documentation, etc.
3.  Pull requests are not merged directly into the master branch.
4.  Code contributions require signing a Google CLA.

API changes
-----------

   * ImmutableList.copyOf} and use that list instead.
   */
  public List<Integer> asList() {
    /*
     * Typically we cache this kind of thing, but much repeated use of this view is a performance
     * anti-pattern anyway. If we cache, then everyone pays a price in memory footprint even if
     * they never use this method.
     */
    return new AsList(this);
  }

   * and use that list instead.
   */
  public List<Long> asList() {
    /*
     * Typically we cache this kind of thing, but much repeated use of this view is a performance
     * anti-pattern anyway. If we cache, then everyone pays a price in memory footprint even if
     * they never use this method.
     */
    return new AsList(this);
  }

    assertThrows(IndexOutOfBoundsException.class, () -> iia3.subArray(1, 4));
  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    char[][] arrays = new char[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    char[] sharedArray = new char[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Chars.concat(arrays);
      fail();
    } catch (IllegalArgumentException expected) {

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    double[][] arrays = new double[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    double[] sharedArray = new double[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Doubles.concat(arrays);
      fail();
    } catch (IllegalArgumentException expected) {

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    int[][] arrays = new int[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    int[] sharedArray = new int[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Ints.concat(arrays);
      fail();
    } catch (IllegalArgumentException expected) {
    }

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    boolean[][] arrays = new boolean[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    boolean[] sharedArray = new boolean[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Booleans.concat(arrays);
      fail();

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    short[][] arrays = new short[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    short[] sharedArray = new short[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Shorts.concat(arrays);
      fail();
    } catch (IllegalArgumentException expected) {