You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_gem_commands_which_command.rb
    path of file: ./repos/ruby-packer/ruby/test/rubygems
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
require 'rubygems/test_case'
require 'rubygems/commands/which_command'

class TestGemCommandsWhichCommand < Gem::TestCase

  def setup
    super

    
  def test_execute_directory
    @cmd.handle_options %w[directory]

    use_ui @ui do
      assert_raises Gem::MockGemUi::TermError do
        @cmd.execute
      end
    end

    assert_equal '', @ui.output
    assert_match %r%Can.t find Ruby library file or shared library directory\n%,
                 @ui.error
  end