202E; RIGHT-TO-LEFT OVERRIDE
   206A; INHIBIT SYMMETRIC SWAPPING
   206B; ACTIVATE SYMMETRIC SWAPPING
   206C; INHIBIT ARABIC FORM SHAPING
   206D; ACTIVATE ARABIC FORM SHAPING
   206E; NATIONAL DIGIT SHAPES

    assertThat(stringPrep("\u200e")).isNull() // LEFT-TO-RIGHT MARK
    assertThat(stringPrep("\u206e")).isNull() // NATIONAL DIGIT SHAPES
    assertThat(stringPrep("\u206f")).isNull() // NOMINAL DIGIT SHAPES
  }

  @Test fun prohibitionTaggingCharacters() {
    assertThat(stringPrep("\udb40\udc01")).isNull() // Note that this is one code point.

    this.port = port;
  }

  /** See https://api.slack.com/docs/oauth. */
  public HttpUrl authorizeUrl(String scopes, HttpUrl redirectUrl, ByteString state, String team) {
    HttpUrl.Builder builder = baseUrl.newBuilder("/oauth/authorize")
        .addQueryParameter("client_id", clientId)
        .addQueryParameter("scope", scopes)
        .addQueryParameter("redirect_uri", redirectUrl.toString())
        .addQueryParameter("state", state.base64());

import org.junit.jupiter.api.extension.ParameterResolver

/**
 * Runs MockWebServer for the duration of a single test method.
 *
 * Specifically while junit instances passes into test constructor
 * are typically shares amongst all tests, a fresh instance will be
 * received here. Use with @BeforeAll and @AfterAll, is not supported.
 *
 * There are 3 ids for instances
 * - The test instance default (passed into constructor)

  /** Shows a browser URL to authorize this app to act as this user. */
  public void requestOauthSession(String scopes, String team) throws Exception {
    if (sessionFactory == null) {
      sessionFactory = new OAuthSessionFactory(slackApi);
      sessionFactory.start();
    }

    HttpUrl authorizeUrl = sessionFactory.newAuthorizeUrl(scopes, team, session -> {
      initOauthSession(session);
      System.out.printf("session granted: %s\n", session);

    this.executorServiceOrNull = executorService
  }

  internal fun enqueue(call: AsyncCall) {
    this.withLock {
      readyAsyncCalls.add(call)

      // Mutate the AsyncCall so that it shares the AtomicInteger of an existing running call to
      // the same host.
      if (!call.call.forWebSocket) {
        val existingCall = findExistingCallWithHost(call.host)