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) {

    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) {

  }

  /**
   * Returns {@code n} choose {@code k}, also known as the binomial coefficient of {@code n} and
   * {@code k}, that is, {@code n! / (k! (n - k)!)}.
   *
   * <p><b>Warning:</b> the result can take as much as <i>O(k log n)</i> space.
   *
   * @throws IllegalArgumentException if {@code n < 0}, {@code k < 0}, or {@code k > n}
   */
  public static BigInteger binomial(int n, int k) {
    checkNonNegative("n", n);

    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(notification.getValue()).isEqualTo("a");
    assertThat(cache.size()).isEqualTo(1);
    assertThat(cache.getUnchecked("b")).isEqualTo("b");
  }

  // "Basher tests", where we throw a bunch of stuff at a LoadingCache and check basic invariants.

  /**
   * This is a less carefully-controlled version of {@link #testRemovalNotification_clear} - this is

   * higher value than you need can waste space and time, and a significantly lower value can lead
   * to thread contention. But overestimates and underestimates within an order of magnitude do not
   * usually have much noticeable impact. A value of one permits only one thread to modify the cache
   * at a time, but since read operations and cache loading computations can proceed concurrently,

    long start1 = System.currentTimeMillis();
    SmbFile[] files1 = dir.listFiles();
    long time1 = System.currentTimeMillis() - start1;
    
    // Second listing should use cache (much faster)
    long start2 = System.currentTimeMillis();
    SmbFile[] files2 = dir.listFiles();
    long time2 = System.currentTimeMillis() - start2;
    
    assertEquals(files1.length, files2.length);

    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) {

 * order to {@code [key2, key1]}. The {@link #entries()} iterator returns mutable map entries, and
 * {@link #replaceValues} attempts to preserve iteration order as much as possible.
 *
 * <p>The collections returned by {@link #keySet()} and {@link #asMap()} iterate through the keys in
 * the order they were first added to the multimap. Similarly, {@link #get}, {@link #removeAll}, and

   * input byte array {@code {0x54, 0x32}} would yield the {@code short} value {@code 0x5432}.
   *
   * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more
   * flexibility at little cost in readability.
   *
   * @throws IllegalArgumentException if {@code bytes} has fewer than 2 elements
   */
  @GwtIncompatible // doesn't work