* the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullKeyMissingWhenNullKeysUnsupported(String message) {
    try {
      assertFalse(message, getMap().containsKey(null));
    } catch (NullPointerException tolerated) {

   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullMissingWhenNullUnsupported(String message) {
    try {
      assertFalse(message, actualContents().contains(null));
    } catch (NullPointerException tolerated) {

     * specified for this filter. The wildcard has no influence on this
     * method as the server should have performed that filtering already. The
     * attributes are asserted here only because server file systems may not
     * support filtering by all attributes (e.g. even though ATTR_DIRECTORY was
     * specified the server may still return objects that are not directories).
     */
    @Override

    for (K k : sampleKeys()) {
      resetContainer();

      List<V> expectedValues = copyToList(multimap().get(k));

      assertTrue(multimap().putAll(k, values));
      expectedValues.addAll(values);

      assertGet(k, expectedValues);
    }
  }

    for (K k : sampleKeys()) {
      resetContainer();

      Set<V> expectedValues = copyToSet(multimap().get(k));

      multimap().putAll(k, valuesToPut);
      expectedValues.addAll(valuesToPut);

      assertGet(k, expectedValues);
    }
  }

    assertEmpty(multimap().asMap());
    assertEmpty(multimap().keySet());
    assertEmpty(multimap().keys());
    assertEmpty(multimap().values());
    for (K key : sampleKeys()) {
      assertGet(key);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testClear() {
    multimap().clear();
    assertCleared();
  }

  @MapFeature.Require(SUPPORTS_REMOVE)

    assertThat(events).isEmpty()
  }

  fun assertEvent(
    id: String?,
    type: String?,
    data: String,
  ) {
    assertThat(nextEvent()).isEqualTo(Event(id, type, data))
  }

  fun assertOpen(): EventSource {
    val event = nextEvent() as Open
    return event.eventSource
  }

  fun assertClose() {
    nextEvent() as Closed
  }

  fun assertFailure(message: String?) {

/* This returns true if the file's attributes contain any of the attributes
 * specified for this filter. The wildcard has no influence on this
 * method as the server should have performed that filtering already. The
 * attributes are asserted here only because server file systems may not
 * support filtering by all attributes (e.g. even though ATTR_DIRECTORY was
 * specified the server may still return objects that are not directories).
 */

    }
  }

  /** Returns the product of {@code n1} exclusive through {@code n2} inclusive. */
  @SuppressWarnings("UseCorrectAssertInTests") // TODO(b/345814817): Remove or convert assertion.
  private static BigInteger oldSlowFactorial(int n1, int n2) {
    assert n1 <= n2;
    if (IntMath.log2(n2, CEILING) * (n2 - n1) < Long.SIZE - 1) {
      // the result will definitely fit into a long
      long result = 1;

      @Override
      public int hashCode() {
        return 1;
      }
    }
  }

  private static void assertContains(String expectedSubstring, String actual) {
    // TODO(kevinb): use a Truth assertion here
    if (!actual.contains(expectedSubstring)) {
      fail("expected <" + actual + "> to contain <" + expectedSubstring + ">");
    }
  }