text: # This example code is in the Public Domain (or CC0 licensed, at your option.)
  
  # Unless required by applicable law or agreed to in writing, this
  # software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
  # CONDITIONS OF ANY KIND, either express or implied.
  
  # -*- coding: utf-8 -*-
  
  from __future__ import print_function
  from __future__ import unicode_literals
  import os
  import sys
  import re
  import socket
  import ttfw_idf
  
  
  # -----------  Config  ----------
  PORT = 3333
  INTERFACE = 'eth0'
  # -------------------------------
  
  
  def tcp_client(address, payload):
      for res in socket.getaddrinfo(address, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          family_addr, socktype, proto, canonname, addr = res
      try:
          sock = socket.socket(family_addr, socket.SOCK_STREAM)
      except socket.error as msg:
          print('Could not create socket: ' + str(msg[0]) + ': ' + msg[1])
          raise
      try:
          sock.connect(addr)
      except socket.error as msg:
          print('Could not open socket: ', msg)
          sock.close()
          raise
      sock.sendall(payload.encode())
      data = sock.recv(1024)
      if not data:
          return
      print('Reply : ' + data.decode())
      sock.close()
      return data.decode()
  
  
  @ttfw_idf.idf_example_test(env_tag="Example_WIFI")
  def test_examples_protocol_socket(env, extra_data):
      MESSAGE = "Data to ESP"
      """
      steps:
        1. join AP
        2. have the board connect to the server
        3. send and receive data
      """
      dut1 = env.get_dut("tcp_client", "examples/protocols/sockets/tcp_server", dut_class=ttfw_idf.ESP32DUT)
      # check and log bin size
      binary_file = os.path.join(dut1.app.binary_path, "tcp_server.bin")
      bin_size = os.path.getsize(binary_file)
      ttfw_idf.log_performance("tcp_server_bin_size", "{}KB".format(bin_size // 1024))
  
      # start test
      dut1.start_app()
  
      ipv4 = dut1.expect(re.compile(r" IPv4 address: ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)"), timeout=30)[0]
      ipv6_r = r':'.join((r'[0-9a-fA-F]{4}',) * 8)    # expect all 8 octets from IPv6 (assumes it's printed in the long form)
      ipv6 = dut1.expect(re.compile(r' IPv6 address: ({})'.format(ipv6_r)), timeout=30)[0]
      print("Connected with IPv4={} and IPv6={}".format(ipv4, ipv6))
  
      # test IPv4
      received = tcp_client(ipv4, MESSAGE)
      if not received == MESSAGE:
          raise
      dut1.expect(MESSAGE)
      # test IPv6
      received = tcp_client("{}%{}".format(ipv6, INTERFACE), MESSAGE)
      if not received == MESSAGE:
          raise
      dut1.expect(MESSAGE)
  
  
  if __name__ == '__main__':
      if sys.argv[2:]:    # if two arguments provided:
          # Usage: example_test.py <server_address> <message_to_send_to_server>
          tcp_client(sys.argv[1], sys.argv[2])
      else:               # otherwise run standard example test as in the CI
          test_examples_protocol_socket()
  