Iterator<String> iterator = asList("one", "two").iterator();
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> getOnlyElement(iterator));
    assertThat(expected).hasMessageThat().isEqualTo("expected one element but was: <one, two>");
  }

  public void testGetOnlyElement_noDefault_fiveElements() {
    Iterator<String> iterator = asList("one", "two", "three", "four", "five").iterator();

 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.ListFeature.SUPPORTS_ADD_WITH_INDEX;

   */
  boolean isEmpty();

  /**
   * Returns {@code true} if this multimap contains at least one key-value pair with the key {@code
   * key}.
   */
  boolean containsKey(@CompatibleWith("K") @Nullable Object key);

  /**
   * Returns {@code true} if this multimap contains at least one key-value pair with the value
   * {@code value}.
   */

   * list with one before {@code index}. Under these circumstances it returns a pair of elements as
   * a {@link MoveDesc}. The first one is the element that was previously at the end of the heap and
   * is now at some position before {@code index}. The second element is the one that was swapped

    sizesToTest.retainAll(features);
    features.removeAll(sizesToTest);

    addImpliedFeatures(sizesToTest);
    sizesToTest.retainAll(asList(CollectionSize.ZERO, CollectionSize.ONE, CollectionSize.SEVERAL));

    logger.fine("   Sizes: " + formatFeatureSet(sizesToTest));

    if (sizesToTest.isEmpty()) {
      throw new IllegalStateException(
          name

 *       suite()} method with {@code Suppress}. Would {@code FooTest} itself be suppressed, too?
 *   <li>In at least one case, a use of {@code sun.misc.FpUtils}, the test will not even
 *       <i>compile</i> against Android. Now, this might be an artifact of our build system, one
 *       that we could probably work around. Or we could manually strip the test from open-source

   *
   * @return {@code true} if the graph was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean addNode(N node);

  /**
   * Adds an edge connecting {@code nodeU} to {@code nodeV} if one is not already present.
   *
   * <p>If the graph is directed, the resultant edge will be directed; otherwise, it will be
   * undirected.
   *

 * </ul>
 *
 * <p>The set of supported keys will grow as {@code CacheBuilder} evolves, but existing keys will
 * never be removed.
 *
 * <p>Durations are represented by an integer, followed by one of "d", "h", "m", or "s",
 * representing days, hours, minutes, or seconds respectively. (There is currently no syntax to
 * request expiration in milliseconds, microseconds, or nanoseconds.)
 *

 * </ul>
 *
 * <p>The set of supported keys will grow as {@code CacheBuilder} evolves, but existing keys will
 * never be removed.
 *
 * <p>Durations are represented by an integer, followed by one of "d", "h", "m", or "s",
 * representing days, hours, minutes, or seconds respectively. (There is currently no syntax to
 * request expiration in milliseconds, microseconds, or nanoseconds.)
 *

    return atomic == null ? 0L : atomic.get();
  }

  /**
   * Increments by one the value currently associated with {@code key}, and returns the new value.
   */
  @CanIgnoreReturnValue
  public long incrementAndGet(K key) {
    return addAndGet(key, 1);
  }

  /**
   * Decrements by one the value currently associated with {@code key}, and returns the new value.
   */
  @CanIgnoreReturnValue