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[] {1.0f, 1.0f, 1.0f});
    assertThat(Floats.concat(ARRAY1, ARRAY234)).isEqualTo(new float[] {1.0f, 2.0f, 3.0f, 4.0f});
  }

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

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

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

          array[i] = counter.getAndIncrement();
        }
        builder.addAll(ImmutableLongArray.copyOf(array));
      }
    },
    ADD_LARGER_ARRAY {
      @Override
      void doIt(ImmutableLongArray.Builder builder, AtomicLong counter) {
        long[] array = new long[random.nextInt(200) + 200];
        for (int i = 0; i < array.length; i++) {
          array[i] = counter.getAndIncrement();
        }

    E[] array = (E[]) Iterables.toArray(elements);
    checkElementsNotNull(array);
    Arrays.sort(array, comparator);
    return asImmutableList(array);
  }

  private static <E> List<E> nullCheckedList(Object... array) {
    for (int i = 0, len = array.length; i < len; i++) {
      if (array[i] == null) {
        throw new NullPointerException("at index " + i);
      }
    }

    return CompactHashSet.create();
  }

  /**
   * Returns a new array of the given length with the same type as a reference array.
   *
   * @param reference any array of the desired type
   * @param length the length of the new array
   */
  /*
   * The new array contains nulls, even if the old array did not. If we wanted to be accurate, we

  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)

        this.output = output == null ? null : output.replace("\n", " ");
        Arrays.sort(inputs);

        if (id == 0) {
            // create
            newInputs = inputs;
            newOutput = output;
        }
    }

    /**
     * Returns the array of new input character sequences for update operations.
     *
     * @return array of new input sequences, or null if no updates are pending
     */

    }

    /**
     * Returns the array of values associated with this request parameter.
     *
     * @return the parameter values array, may be null or empty
     */
    public String[] getValues() {
        return values;
    }

    /**
     * Returns a string representation of this RequestParameter.
     * The format includes the parameter name and its values in array format.
     *

    return CompactHashSet.create();
  }

  /**
   * Returns a new array of the given length with the same type as a reference array.
   *
   * @param reference any array of the desired type
   * @param length the length of the new array
   */
  /*
   * The new array contains nulls, even if the old array did not. If we wanted to be accurate, we