*
   * @throws IllegalArgumentException if {@code n < 0}
   */
  @GwtIncompatible // TODO
  public static long factorial(int n) {
    checkNonNegative("n", n);
    return (n < factorials.length) ? factorials[n] : Long.MAX_VALUE;
  }

  static final long[] factorials = {
    1L,
    1L,
    1L * 2,
    1L * 2 * 3,
    1L * 2 * 3 * 4,
    1L * 2 * 3 * 4 * 5,
    1L * 2 * 3 * 4 * 5 * 6,

  private lateinit var client: OkHttpClient

  @BeforeEach
  fun setUp() {
    // Sockets on some platforms can have large buffers that mean writes do not block when
    // required. These socket factories explicitly set the buffer sizes on sockets created.
    server = MockWebServer()
    server.serverSocketFactory =
      object : DelegatingServerSocketFactory(getDefault()) {
        @Throws(SocketException::class)