new_contents: import pytest
  import ipaddress
  from lab import network
  
  
  @pytest.mark.parametrize('ip', [
      '127.0.0.1',
      '::1'
  ])
  def test_ping(ip):
      network.ping(ip)
  
  
  @pytest.mark.parametrize('ip, expected', [
      ('127.0.0.1', 4),
      ('::1', 6)
  ])
  def test_addr_version_detection(ip, expected):
      assert network.get_addr_version(ip) == expected
  
  
  @pytest.mark.parametrize('ip, version, expected', [
      ('127.0.0.1', 4, ipaddress.IPv4Address(u'127.0.0.1')),
      ('::1', 6, ipaddress.IPv6Address(u'::1')),
      ('localhost.localdomain', 4, ipaddress.IPv4Address(u'127.0.0.1'))
  ])
  def test_check_ipaddr(ip, version, expected):
      assert network.check_ipaddr(ip, version=version) == (expected, ip)
  
  
  @pytest.mark.parametrize('destination, version, expected', [
      ('localhost', 4, 'lo'),
  ])
  def test_find_best_route(destination, version, expected):
      iface, addr = network.find_best_route(destination, version=version)
      assert iface == expected
      assert addr.version == version
  
subject: Add a set of tests for the network module