server.enqueue(MockResponse())

    val clientCertificates =
      HandshakeCertificates
        .Builder()
        .addPlatformTrustedCertificates()
        .addInsecureHost(server.hostName)
        .build()

    val client =
      clientTestRule
        .newClientBuilder()
        .sslSocketFactory(clientCertificates.sslSocketFactory(), clientCertificates.trustManager)

    assumeTrue(Build.VERSION.SDK_INT >= 24)

    val clientCertificates =
      HandshakeCertificates
        .Builder()
        .apply {
          if (Build.VERSION.SDK_INT >= 24) {
            addInsecureHost(server.hostName)
          }
        }.build()

    client =
      client
        .newBuilder()
        .sslSocketFactory(clientCertificates.sslSocketFactory(), clientCertificates.trustManager)

     * a mechanism to trust some hosts and not others.
     *
     * @param hostname the exact hostname from the URL for insecure connections.
     */
    fun addInsecureHost(hostname: String) =
      apply {
        insecureHosts += hostname
      }

    fun build(): HandshakeCertificates {
      val immutableInsecureHosts = insecureHosts.toImmutableList()