expectUnchanged();
  }

  // retainAll(sameElements)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRetainAll_sameElements() {
    expectReturnsFalse(sameElements);
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testRetainAll_sameElementsUnsupported() {
    expectReturnsFalseOrThrows(sameElements);
    expectUnchanged();
  }

    expectUnchanged();
  }

  // retainAll(sameElements)

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRetainAll_sameElements() {
    expectReturnsFalse(sameElements);
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testRetainAll_sameElementsUnsupported() {
    expectReturnsFalseOrThrows(sameElements);
    expectUnchanged();
  }

    assertTrue(
        "containsAll(subset) should return true",
        collection.containsAll(MinimalCollection.of(e0())));
  }

  public void testContainsAll_sameElements() {
    assertTrue(
        "containsAll(sameElements) should return true",
        collection.containsAll(MinimalCollection.of(createSamplesArray())));
  }

  @SuppressWarnings("ModifyingCollectionWithItself")
  public void testContainsAll_self() {