shadowDns.responder = {
      throw IllegalArgumentException("Network.fromNetworkHandle refusing to instantiate NETID_UNSET Network.")
    }

    val dns = AsyncDns.toDns(asyncDns)

    assertFailure {
      dns.lookup("google.invalid")
    }.apply {
      hasMessage("Network.fromNetworkHandle refusing to instantiate NETID_UNSET Network.")
      isInstanceOf(UnknownHostException::class)
    }
  }

  @JvmField @Rule
  val serverRule = MockWebServerRule()
  private lateinit var client: OkHttpClient

  private val localhost: HandshakeCertificates by lazy {
    // Generate a self-signed cert for the server to serve and the client to trust.
    val heldCertificate =
      HeldCertificate.Builder()
        .addSubjectAlternativeName("localhost")
        .build()
    return@lazy HandshakeCertificates.Builder()