text: import subprocess
  import pytest
  
  from pikka_bird_collector.collectors.base_port_command import BasePortCommand
  
  
  class TestBasePortCommand:
      
      COMMAND_OK          = ['echo', 'HELLO']
      COMMAND_ERR_STATUS  = ['test', '-f', '__666__']
      COMMAND_ERR_MISSING = ['echoooooooooo']
      
      def test_exec_command(self):
          assert BasePortCommand.exec_command(self.COMMAND_OK) == 'HELLO\n'
      
      def test_exec_command_status(self):
          assert BasePortCommand.exec_command(self.COMMAND_ERR_STATUS) == None
      
      def test_exec_command_missing(self):
          assert BasePortCommand.exec_command(self.COMMAND_ERR_MISSING) == None
  