text: import pytest
  
  from pip.exceptions import CommandError
  from pip.basecommand import ERROR, SUCCESS
  from pip.commands.help import HelpCommand
  from pip.commands import commands_dict as commands
  from mock import Mock
  
  
  def test_run_method_should_return_success_when_finds_command_name():
      """
      Test HelpCommand.run for existing command
      """
      options_mock = Mock()
      args = ('freeze',)
      help_cmd = HelpCommand()
      status = help_cmd.run(options_mock, args)
      assert status == SUCCESS
  
  
  def test_run_method_should_return_success_when_command_name_not_specified():
      """
      Test HelpCommand.run when there are no args
      """
      options_mock = Mock()
      args = ()
      help_cmd = HelpCommand()
      status = help_cmd.run(options_mock, args)
      assert status == SUCCESS
  
  
  def test_run_method_should_raise_command_error_when_command_does_not_exist():
      """
      Test HelpCommand.run for non-existing command
      """
      options_mock = Mock()
      args = ('mycommand',)
      help_cmd = HelpCommand()
  
      with pytest.raises(CommandError):
          help_cmd.run(options_mock, args)
  
  
  def test_help_command_should_exit_status_ok_when_command_exists(script):
      """
      Test `help` command for existing command
      """
      result = script.pip('help', 'freeze')
      assert result.returncode == SUCCESS
  
  
  def test_help_command_should_exit_status_ok_when_no_cmd_is_specified(script):
      """
      Test `help` command for no command
      """
      result = script.pip('help')
      assert result.returncode == SUCCESS
  
  
  def test_help_command_should_exit_status_error_when_cmd_does_not_exist(script):
      """
      Test `help` command for non-existing command
      """
      result = script.pip('help', 'mycommand', expect_error=True)
      assert result.returncode == ERROR
  
  
  def test_help_commands_equally_functional(in_memory_pip):
      """
      Test if `pip help` and 'pip --help' behave the same way.
      """
      results = list(map(in_memory_pip.pip, ('help', '--help')))
      results.append(in_memory_pip.pip())
  
      out = map(lambda x: x.stdout, results)
      ret = map(lambda x: x.returncode, results)
  
      msg = '"pip --help" != "pip help" != "pip"'
      assert len(set(out)) == 1, 'output of: ' + msg
      assert sum(ret) == 0, 'exit codes of: ' + msg
      assert all(len(o) > 0 for o in out)
  
      for name, cls in commands.items():
          if cls.hidden:
              continue
  
          assert (
              in_memory_pip.pip('help', name).stdout ==
              in_memory_pip.pip(name, '--help').stdout != ""
          )
  