assertThat(Floats.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Floats.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Floats.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Floats.concat(ARRAY1, ARRAY1, ARRAY1))
        .isEqualTo(new float[] {(float) 1, (float) 1, (float) 1});
    assertThat(Floats.concat(ARRAY1, ARRAY234))

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates_nullDuplicatesNotRejected() {
    E[] array = createArrayWithNullElement();
    array[0] = null;
    collection = getSubjectGenerator().create(array);

    List<E> expectedWithDuplicateRemoved = Arrays.asList(array).subList(1, getNumElements());
    expectContents(expectedWithDuplicateRemoved);
  }

        builder.add(counter.getAndIncrement());
      }
    },
    ADD_ARRAY {
      @Override
      void doIt(ImmutableLongArray.Builder builder, AtomicLong counter) {
        long[] array = new long[RANDOM.nextInt(10)];
        for (int i = 0; i < array.length; i++) {
          array[i] = counter.getAndIncrement();
        }
        builder.addAll(array);
      }
    },
    ADD_COLLECTION {
      @Override

  public void testRetainAll_duplicatesKept() {
    E[] array = createSamplesArray();
    array[1] = e0();
    collection = getSubjectGenerator().create(array);
    assertFalse(
        "containsDuplicates.retainAll(superset) should return false",
        collection.retainAll(MinimalCollection.of(createSamplesArray())));
    expectContents(array);
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

  private static final int[] exponents = new int[ARRAY_SIZE];
  private static final int[] factorialArguments = new int[ARRAY_SIZE];
  private static final int[][] binomialArguments = new int[ARRAY_SIZE][2];
  private static final long[] positive = new long[ARRAY_SIZE];
  private static final long[] nonnegative = new long[ARRAY_SIZE];
  private static final long[] longs = new long[ARRAY_SIZE];

  @BeforeExperiment
  void setUp() {

  }

  /**
   * @return an array of the proper size with {@code null} as the key of the middle element.
   */
  protected Entry<K, V>[] createArrayWithNullKey() {
    Entry<K, V>[] array = createSamplesArray();
    int nullKeyLocation = getNullLocation();
    Entry<K, V> oldEntry = array[nullKeyLocation];
    array[nullKeyLocation] = Helpers.mapEntry(null, oldEntry.getValue());
    return array;
  }

  /**

    assertThat(Longs.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Longs.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Longs.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Longs.concat(ARRAY1, ARRAY1, ARRAY1))
        .isEqualTo(new long[] {(long) 1, (long) 1, (long) 1});
    assertThat(Longs.concat(ARRAY1, ARRAY234))

    assertThat(Longs.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Longs.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Longs.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Longs.concat(ARRAY1, ARRAY1, ARRAY1))
        .isEqualTo(new long[] {(long) 1, (long) 1, (long) 1});
    assertThat(Longs.concat(ARRAY1, ARRAY234))

  private final int end; // exclusive

  private ImmutableLongArray(long[] array) {
    this(array, 0, array.length);
  }

  private ImmutableLongArray(long[] array, int start, int end) {
    this.array = array;
    this.start = start;
    this.end = end;
  }

  /** Returns the number of values in this array. */
  public int length() {
    return end - start;
  }

  private final int[] factorials = new int[ARRAY_SIZE];
  private final int[][] binomials = new int[ARRAY_SIZE][2];
  private final int[][] nonnegInt = new int[ARRAY_SIZE][2];
  private final long[][] nonnegLong = new long[ARRAY_SIZE][2];
  private final int[][] intsToAdd = new int[ARRAY_SIZE][2];
  private final int[][] intsToMul = new int[ARRAY_SIZE][2];
  private final long[][] longsToAdd = new long[ARRAY_SIZE][2];