private @Nullable EnumSet<E> set;

    void add(E e) {
      if (set == null) {
        set = EnumSet.of(e);
      } else {
        set.add(e);
      }
    }

    EnumSetAccumulator<E> combine(EnumSetAccumulator<E> other) {
      if (this.set == null) {
        return other;
      } else if (other.set == null) {
        return this;
      } else {
        this.set.addAll(other.set);

    private var bodyVar: MockResponseBody? = null
    private var socketHandlerVar: SocketHandler? = null
    private var webSocketListenerVar: WebSocketListener? = null

    public var body: MockResponseBody?
      get() = bodyVar
      private set(value) {
        bodyVar = value
        socketHandlerVar = null
        webSocketListenerVar = null
      }

    notEqualObject1 = new ValidTestObject(0, 2);
  }

  /** Test null reference yields error */
  public void testAddNullReference() {
    assertThrows(NullPointerException.class, () -> equalsTester.addEqualityGroup((Object) null));
  }

  /** Test equalObjects after adding multiple instances at once with a null */
  public void testAddTwoEqualObjectsAtOnceWithNull() {
    assertThrows(

      |--123--
      |
      """.trimMargin().replace("\n", "\r\n")
    val body =
      MultipartBody
        .Builder("123")
        .addPart("Quick".toRequestBody(null))
        .addPart("Brown".toRequestBody(null))
        .addPart("Fox".toRequestBody(null))
        .build()
    assertThat(body.boundary).isEqualTo("123")
    assertThat(body.type).isEqualTo(MultipartBody.MIXED)
    assertThat(body.contentType().toString())

                null,
                dependency.getType()));
    }

    @Nonnull
    default DependencyCoordinates create(@Nonnull Session session, Plugin plugin) {
        // TODO: hard coded string
        return create(DependencyCoordinatesFactoryRequest.build(
                session, plugin.getGroupId(), plugin.getArtifactId(), plugin.getVersion(), null, null, "maven-plugin"));
    }

    @Nonnull

    @Test
    void testVersionlessManagedDependency() throws Exception {
        File pomFile = new File("src/test/resources/projects/versionless-managed-dependency.xml");
        MavenSession mavenSession = createMavenSession(null);
        ProjectBuildingRequest configuration = new DefaultProjectBuildingRequest();
        configuration.setRepositorySession(mavenSession.getRepositorySession());

import okio.ByteString.Companion.encodeUtf8
import okio.IOException
import okio.Source
import okio.buffer

class ResponseBodyTest {
  @Test
  fun sourceEmpty() {
    val mediaType = if (null == null) null else "any/thing; charset=${null}".toMediaType()
    val body = "".decodeHex().toResponseBody(mediaType)
    val source = body.source()
    assertThat(source.exhausted()).isTrue()
    assertThat(source.readUtf8()).isEqualTo("")
  }

        // Intentionally notNull because Super POM may not contain a modelId
        Objects.requireNonNull(modelId, "modelId cannot null");

        if (activeProfiles != null) {
            this.activePomProfiles.put(modelId, new ArrayList<>(activeProfiles));
        } else {
            this.activePomProfiles.remove(modelId);
        }

        return this;

        this.lookup = requireNonNull(lookup, "lookup cannot be null");
        this.languageRegistry = requireNonNull(languageRegistry, "languageRegistry cannot be null");
        this.usedTypes = new ConcurrentHashMap<>();
        this.manager = requireNonNull(manager, "artifactHandlerManager cannot be null");
    }

    @Override
    public void onEvent(Object event) {

     *
     * @return The group id, never {@code null}.
     */
    String getGroupId();

    /**
     * Gets the artifact id of the constituent's artifact.
     *
     * @return The artifact id, never {@code null}.
     */
    String getArtifactId();

    /**
     * Gets the type of the constituent's artifact.
     *
     * @return The type, never {@code null}.
     */
    String getType();

    /**