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_signin_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/signin_command'
require 'rubygems/installer'

class TestGemCommandsSigninCommand < Gem::TestCase

  def setup
    super

    Gem.configuration.rubygems_api_key = nil
    Gem.configuration.a
    
  def test_execute_with_host_supplied
    host = 'http://some-gemcutter-compatible-host.org'

    sign_in_ui = util_capture(nil, host) { @cmd.execute }
    assert_match %r{Enter your #{host} credentials.}, sign_in_ui.output
    assert_match %r{Signed in.}, sign_in_ui.output

    api_key     = 'a5fdbb6ba150cbb83aad2bb2fede64cf040453903'
    credentials = YAML.load_file Gem.configuration.credentials_path
    assert_equal api_key, credentials[host]
  end