public void testCreateFromHashMultimap() {
    Multimap<Double, Double> hash = HashMultimap.create();
    hash.put(1.0, 2.0);
    hash.put(2.0, 3.0);
    hash.put(3.0, 4.0);
    hash.put(4.0, 5.0);

    TreeMultimap<Double, Double> copyFromHash = TreeMultimap.create(hash);
    assertEquals(hash, copyFromHash);
    assertEquals(Ordering.natural(), copyFromHash.keyComparator());

      String error = errorMessage.get();
      assertNull(error, error);
    }
    executor.shutdown();
  }

  /**
   * He did the bash, he did the future bash The future bash, it was a concurrency smash He did the
   * bash, it caught on in a flash He did the bash, he did the future bash
   */

  public void testFutureBash() {
    if (isWindows()) {
      return; // TODO: b/136041958 - Running very slowly on Windows CI.

    collection = getSubjectGenerator().create(elements.toArray());
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements (with "
            + "a null element counting as having a hash of zero).",
        expectedHashCode,
        getSet().hashCode());
  }

  /**
   * Returns the {@link Method} instances for the test methods in this class which call {@code

        .testEquals();
  }

  /**
   * The maximum allowed probability of falsely detecting a hash flooding attack if the input is
   * randomly generated.
   */
  private static final double HASH_FLOODING_FPP = 0.001;

  public void testReuseBuilderReducingHashTableSizeWithPowerOfTwoTotalElements() {

   */
  @Override
  public abstract boolean equals(@CheckForNull Object object);

  /**
   * Returns a hash code for this instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> this class leaves the specific choice of
   * hash code unspecified, unlike the Java 8+ equivalent.
   */
  @Override
  public abstract int hashCode();

  /**

    Map<ClassWithTerribleHashCode, Integer> expected = new LinkedHashMap<>();
    Builder<ClassWithTerribleHashCode, Integer> builder = new Builder<>();
    int size = RegularImmutableMap.MAX_HASH_BUCKET_LENGTH + 10;
    for (int i = 0; i < size; i++) {
      ClassWithTerribleHashCode key = new ClassWithTerribleHashCode(i);
      builder.put(key, i);
      builder.put(key, -i);
      expected.put(key, -i);

      Maps.capacity(-1);
      fail("Negative expected size must result in IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  /**
   * Tests that nHMWES makes hash maps large enough that adding the expected number of elements
   * won't cause a rehash.
   *
   * <p>As of jdk7u40, HashMap has an empty-map optimization. The argument to new HashMap(int) is

      Maps.capacity(-1);
      fail("Negative expected size must result in IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  /**
   * Tests that nHMWES makes hash maps large enough that adding the expected number of elements
   * won't cause a rehash.
   *
   * <p>As of jdk7u40, HashMap has an empty-map optimization. The argument to new HashMap(int) is

    if (key == null) {
      return null;
    }
    int hash = hash(key);
    return segmentFor(hash).getEntry(key, hash);
  }

  @Override
  public boolean containsKey(@CheckForNull Object key) {
    if (key == null) {
      return false;
    }
    int hash = hash(key);
    return segmentFor(hash).containsKey(key, hash);
  }

  @Override

   * input.
   */
  @VisibleForTesting(
      )
  static final double HASH_FLOODING_FPP = 0.001;

  /**
   * Maximum allowed length of a hash table bucket before falling back to a j.u.LinkedHashSet based
   * implementation. Experimentally determined.
   */
  private static final int MAX_HASH_BUCKET_LENGTH = 9;