ruby--ruby/test/rubygems/test_require.rb

# frozen_string_literal: true
require_relative 'helper'
require 'rubygems'

class TestGemRequire < Gem::TestCase
  class Latch
    def initialize(count = 1)
      @count = count
      @lock  = Monitor.new
      @cv    = @lock.new_cond
    end

    def release
      @lock.synchronize do
        @count -= 1 if @count > 0
        @cv.broadcast if @count.zero?
      end
    end

    def await
      @lock.synchronize do
        @cv.wait_while { @count > 0 }
      end
    end
  end

  def assert_require(path)
    assert require(path), "'#{path}' was already required"
  end

  def refute_require(path)
    refute require(path), "'#{path}' was not yet required"
  end

  def test_respect_loaded_features_caching_like_standard_require
    dir = Dir.mktmpdir("test_require", @tempdir)

    lp1 = File.join dir, 'foo1'
    foo1 = File.join lp1, 'foo.rb'

    FileUtils.mkdir_p lp1
    File.open(foo1, 'w') {|f| f.write "class Object; HELLO = 'foo1' end" }

    lp = $LOAD_PATH.dup

    $LOAD_PATH.unshift lp1
    assert_require 'foo'
    assert_equal "foo1", ::Object::HELLO

    lp2 = File.join dir, 'foo2'
    foo2 = File.join lp2, 'foo.rb'

    FileUtils.mkdir_p lp2
    File.open(foo2, 'w') {|f| f.write "class Object; HELLO = 'foo2' end" }

    $LOAD_PATH.unshift lp2
    refute_require 'foo'
    assert_equal "foo1", ::Object::HELLO
  ensure
    $LOAD_PATH.replace lp
    Object.send :remove_const, :HELLO if Object.const_defined? :HELLO
  end

  # Providing -I on the commandline should always beat gems
  def test_dash_i_beats_gems
    a1 = util_spec "a", "1", { "b" => "= 1" }, "lib/test_gem_require_a.rb"
    b1 = util_spec "b", "1", { "c" => "> 0" }, "lib/b/c.rb"
    c1 = util_spec "c", "1", nil, "lib/c/c.rb"
    c2 = util_spec "c", "2", nil, "lib/c/c.rb"

    install_specs c1, c2, b1, a1

    dir = Dir.mktmpdir("test_require", @tempdir)
    dash_i_arg = File.join dir, 'lib'

    c_rb = File.join dash_i_arg, 'b', 'c.rb'

    FileUtils.mkdir_p File.dirname c_rb
    File.open(c_rb, 'w') {|f| f.write "class Object; HELLO = 'world' end" }

    # Pretend to provide a commandline argument that overrides a file in gem b
    $LOAD_PATH.unshift dash_i_arg

    assert_require 'test_gem_require_a'
    assert_require 'b/c' # this should be required from -I
    assert_equal "world", ::Object::HELLO
    assert_equal %w[a-1 b-1], loaded_spec_names
  ensure
    Object.send :remove_const, :HELLO if Object.const_defined? :HELLO
  end

  def create_sync_thread
    Thread.new do
      begin
        yield
      ensure
        FILE_ENTERED_LATCH.release
        FILE_EXIT_LATCH.await
      end
    end
  end

  # Providing -I on the commandline should always beat gems
  def test_dash_i_beats_default_gems
    a1 = new_default_spec "a", "1", { "b" => "= 1" }, "test_gem_require_a.rb"
    b1 = new_default_spec "b", "1", { "c" => "> 0" }, "b/c.rb"
    c1 = new_default_spec "c", "1", nil, "c/c.rb"
    c2 = new_default_spec "c", "2", nil, "c/c.rb"

    install_default_gems c1, c2, b1, a1

    dir = Dir.mktmpdir("test_require", @tempdir)
    dash_i_arg = File.join dir, 'lib'

    c_rb = File.join dash_i_arg, 'c', 'c.rb'

    FileUtils.mkdir_p File.dirname c_rb
    File.open(c_rb, 'w') {|f| f.write "class Object; HELLO = 'world' end" }

    assert_require 'test_gem_require_a'

    # Pretend to provide a commandline argument that overrides a file in gem b
    $LOAD_PATH.unshift dash_i_arg

    assert_require 'b/c'
    assert_require 'c/c' # this should be required from -I
    assert_equal "world", ::Object::HELLO
    assert_equal %w[a-1 b-1], loaded_spec_names
  ensure
    Object.send :remove_const, :HELLO if Object.const_defined? :HELLO
  end

  def test_dash_i_respects_default_library_extension_priority
    pend "extensions don't quite work on jruby" if Gem.java_platform?
    pend "not installed yet" unless RbConfig::TOPDIR

    dash_i_ext_arg = util_install_extension_file('a')
    dash_i_lib_arg = util_install_ruby_file('a')

    $LOAD_PATH.unshift dash_i_lib_arg
    $LOAD_PATH.unshift dash_i_ext_arg
    assert_require 'a'
    assert_match(/a\.rb$/, $LOADED_FEATURES.last)
  end

  def test_concurrent_require
    Object.const_set :FILE_ENTERED_LATCH, Latch.new(2)
    Object.const_set :FILE_EXIT_LATCH, Latch.new(1)

    a1 = util_spec "a#{$$}", "1", nil, "lib/a#{$$}.rb"
    b1 = util_spec "b#{$$}", "1", nil, "lib/b#{$$}.rb"

    install_specs a1, b1

    t1 = create_sync_thread { assert_require "a#{$$}" }
    t2 = create_sync_thread { assert_require "b#{$$}" }

    # wait until both files are waiting on the exit latch
    FILE_ENTERED_LATCH.await

    # now let them finish
    FILE_EXIT_LATCH.release

    assert t1.join, "thread 1 should exit"
    assert t2.join, "thread 2 should exit"
  ensure
    Object.send :remove_const, :FILE_ENTERED_LATCH if Object.const_defined? :FILE_ENTERED_LATCH
    Object.send :remove_const, :FILE_EXIT_LATCH if Object.const_defined? :FILE_EXIT_LATCH
  end

  def test_require_is_not_lazy_with_exact_req
    a1 = util_spec "a", "1", { "b" => "= 1" }, "lib/test_gem_require_a.rb"
    b1 = util_spec "b", "1", nil, "lib/b/c.rb"
    b2 = util_spec "b", "2", nil, "lib/b/c.rb"

    install_specs b1, b2, a1

    assert_require 'test_gem_require_a'
    assert_equal %w[a-1 b-1], loaded_spec_names
    assert_equal unresolved_names, []

    assert_require "b/c"
    assert_equal %w[a-1 b-1], loaded_spec_names
  end

  def test_require_is_lazy_with_inexact_req
    a1 = util_spec "a", "1", { "b" => ">= 1" }, "lib/test_gem_require_a.rb"
    b1 = util_spec "b", "1", nil, "lib/b/c.rb"
    b2 = util_spec "b", "2", nil, "lib/b/c.rb"

    install_specs b1, b2, a1

    assert_require 'test_gem_require_a'
    assert_equal %w[a-1], loaded_spec_names
    assert_equal unresolved_names, ["b (>= 1)"]

    assert_require "b/c"
    assert_equal %w[a-1 b-2], loaded_spec_names
  end

  def test_require_is_not_lazy_with_one_possible
    a1 = util_spec "a", "1", { "b" => ">= 1" }, "lib/test_gem_require_a.rb"
    b1 = util_spec "b", "1", nil, "lib/b/c.rb"

    install_specs b1, a1

    assert_require 'test_gem_require_a'
    assert_equal %w[a-1 b-1], loaded_spec_names
    assert_equal unresolved_names, []

    assert_require "b/c"
    assert_equal %w[a-1 b-1], loaded_spec_names
  end

  def test_require_can_use_a_pathname_object
    a1 = util_spec "a", "1", nil, "lib/test_gem_require_a.rb"

    install_specs a1

    assert_require Pathname.new 'test_gem_require_a'
    assert_equal %w[a-1], loaded_spec_names
    assert_equal unresolved_names, []
  end

  def test_activate_via_require_respects_loaded_files
    pend "Not sure what's going on. If another spec creates a 'a' gem before
      this test, somehow require will load the benchmark in b, and ignore that the
      stdlib one is already in $LOADED_FEATURES?. Reproducible by running the
      spaceship_specific_file test before this one" if java_platform?

    pend "not installed yet" unless RbConfig::TOPDIR

    lib_dir = File.expand_path("../lib", __dir__)
    rubylibdir = File.realdirpath(RbConfig::CONFIG["rubylibdir"])
    if rubylibdir == lib_dir
      # testing in the ruby repository where RubyGems' lib/ == stdlib lib/
      # In that case we want to move the stdlib lib/ to still be after b-2 in $LOAD_PATH
      lp = $LOAD_PATH.dup
      $LOAD_PATH.delete lib_dir
      $LOAD_PATH.push lib_dir
      load_path_changed = true
    end

    require 'benchmark' # the stdlib

    a1 = util_spec "a", "1", { "b" => ">= 1" }, "lib/test_gem_require_a.rb"
    b1 = util_spec "b", "1", nil, "lib/benchmark.rb"
    b2 = util_spec "b", "2", nil, "lib/benchmark.rb"

    install_specs b1, b2, a1

    # Activates a-1, but not b-1 and b-2
    assert_require 'test_gem_require_a'
    assert_equal %w[a-1], loaded_spec_names
    assert $LOAD_PATH.include? a1.load_paths[0]
    refute $LOAD_PATH.include? b1.load_paths[0]
    refute $LOAD_PATH.include? b2.load_paths[0]

    assert_equal unresolved_names, ["b (>= 1)"]

    # The require('benchmark') below will activate b-2. However, its
    # lib/benchmark.rb won't ever be loaded. The reason is MRI sees that even
    # though b-2 is earlier in $LOAD_PATH it already loaded a benchmark.rb file
    # and that still exists in $LOAD_PATH (further down),
    # and as a result #gem_original_require returns false.
    refute require('benchmark'), "the benchmark stdlib should be recognized as already loaded"

    assert_includes $LOAD_PATH, b2.load_paths[0]
    assert_includes $LOAD_PATH, rubylibdir
    message = proc {
      "this test relies on the b-2 gem lib/ to be before stdlib to make sense\n" +
      $LOAD_PATH.pretty_inspect
    }
    assert_operator $LOAD_PATH.index(b2.load_paths[0]), :<, $LOAD_PATH.index(rubylibdir), message

    # We detected that we should activate b-2, so we did so, but
    # then #gem_original_require decided "I've already got some benchmark.rb" loaded.
    # This case is fine because our lazy loading provided exactly
    # the same behavior as eager loading would have.

    assert_equal %w[a-1 b-2], loaded_spec_names
  ensure
    $LOAD_PATH.replace lp if load_path_changed
  end

  def test_activate_via_require_respects_loaded_default_from_default_gems
    a1 = new_default_spec "a", "1", nil, "a.rb"

    # simulate requiring a default gem before rubygems is loaded
    Kernel.send(:gem_original_require, "a")

    # simulate registering default specs on loading rubygems
    install_default_gems a1

    a2 = util_spec "a", "2", nil, "lib/a.rb"

    install_specs a2

    refute_require 'a'

    assert_equal %w[a-1], loaded_spec_names
  end

  def test_already_activated_direct_conflict
    a1 = util_spec "a", "1", { "b" => "> 0" }
    b1 = util_spec "b", "1", { "c" => ">= 1" }, "lib/ib.rb"
    b2 = util_spec "b", "2", { "c" => ">= 2" }, "lib/ib.rb"
    c1 = util_spec "c", "1", nil, "lib/d.rb"
    c2 = util_spec("c", "2", nil, "lib/d.rb")

    install_specs c1, c2, b1, b2, a1

    a1.activate
    c1.activate
    assert_equal %w[a-1 c-1], loaded_spec_names
    assert_equal ["b (> 0)"], unresolved_names

    assert require("ib")

    assert_equal %w[a-1 b-1 c-1], loaded_spec_names
    assert_equal [], unresolved_names
  end

  def test_multiple_gems_with_the_same_path
    a1 = util_spec "a", "1", { "b" => "> 0", "x" => "> 0" }
    b1 = util_spec "b", "1", { "c" => ">= 1" }, "lib/ib.rb"
    b2 = util_spec "b", "2", { "c" => ">= 2" }, "lib/ib.rb"
    x1 = util_spec "x", "1", nil, "lib/ib.rb"
    x2 = util_spec "x", "2", nil, "lib/ib.rb"
    c1 = util_spec "c", "1", nil, "lib/d.rb"
    c2 = util_spec("c", "2", nil, "lib/d.rb")

    install_specs c1, c2, x1, x2, b1, b2, a1

    a1.activate
    c1.activate
    assert_equal %w[a-1 c-1], loaded_spec_names
    assert_equal ["b (> 0)", "x (> 0)"], unresolved_names

    e = assert_raise(Gem::LoadError) do
      require("ib")
    end

    assert_equal "ib found in multiple gems: b, x", e.message
  end

  def test_unable_to_find_good_unresolved_version
    a1 = util_spec "a", "1", { "b" => "> 0" }
    b1 = util_spec "b", "1", { "c" => ">= 2" }, "lib/ib.rb"
    b2 = util_spec "b", "2", { "c" => ">= 3" }, "lib/ib.rb"

    c1 = util_spec "c", "1", nil, "lib/d.rb"
    c2 = util_spec "c", "2", nil, "lib/d.rb"
    c3 = util_spec "c", "3", nil, "lib/d.rb"

    install_specs c1, c2, c3, b1, b2, a1

    a1.activate
    c1.activate
    assert_equal %w[a-1 c-1], loaded_spec_names
    assert_equal ["b (> 0)"], unresolved_names

    e = assert_raise(Gem::LoadError) do
      require("ib")
    end

    assert_equal "unable to find a version of 'b' to activate", e.message
  end

  def test_require_works_after_cleanup
    a1 = new_default_spec "a", "1.0", nil, "a/b.rb"
    b1 = new_default_spec "b", "1.0", nil, "b/c.rb"
    b2 = new_default_spec "b", "2.0", nil, "b/d.rb"

    install_default_gems a1
    install_default_gems b1
    install_default_gems b2

    # Load default ruby gems fresh as if we've just started a ruby script.
    Gem::Specification.reset
    require 'rubygems'
    Gem::Specification.stubs

    # Remove an old default gem version directly from disk as if someone ran
    # gem cleanup.
    FileUtils.rm_rf(File.join @gemhome, "#{b1.full_name}")
    FileUtils.rm_rf(File.join @gemhome, "specifications", "default", "#{b1.full_name}.gemspec")

    # Require gems that have not been removed.
    assert_require 'a/b'
    assert_equal %w[a-1.0], loaded_spec_names
    assert_require 'b/d'
    assert_equal %w[a-1.0 b-2.0], loaded_spec_names
  end

  def test_require_doesnt_traverse_development_dependencies
    a = util_spec("a#{$$}", "1", nil, "lib/a#{$$}.rb")
    z = util_spec("z", "1", "w" => "> 0")
    w1 = util_spec("w", "1") {|s| s.add_development_dependency "non-existent" }
    w2 = util_spec("w", "2") {|s| s.add_development_dependency "non-existent" }

    install_specs a, w1, w2, z

    assert gem("z")
    assert_equal %w[z-1], loaded_spec_names
    assert_equal ["w (> 0)"], unresolved_names

    assert require("a#{$$}")
  end

  def test_default_gem_only
    default_gem_spec = new_default_spec("default", "2.0.0.0",
                                        nil, "default/gem.rb")
    install_default_gems(default_gem_spec)
    assert_require "default/gem"
    assert_equal %w[default-2.0.0.0], loaded_spec_names
  end

  def test_default_gem_require_activates_just_once
    default_gem_spec = new_default_spec("default", "2.0.0.0",
                                        nil, "default/gem.rb")
    install_default_gems(default_gem_spec)

    assert_require "default/gem"

    times_called = 0

    Kernel.stub(:gem, ->(name, requirement) { times_called += 1 }) do
      refute_require "default/gem"
    end

    assert_equal 0, times_called
  end

  def test_second_gem_require_does_not_resolve_path_manually_before_going_through_standard_require
    a1 = util_spec "a", "1", nil, "lib/test_gem_require_a.rb"
    install_gem a1

    assert_require "test_gem_require_a"

    stub(:gem_original_require, ->(path) { assert_equal "test_gem_require_a", path }) do
      require "test_gem_require_a"
    end
  end

  def test_realworld_default_gem
    omit "this test can't work under ruby-core setup" if ruby_repo?

    cmd = <<-RUBY
      $stderr = $stdout
      require "json"
      puts Gem.loaded_specs["json"]
    RUBY
    output = Gem::Util.popen(*ruby_with_rubygems_in_load_path, "-e", cmd).strip
    assert $?.success?
    refute_empty output
  end

  def test_realworld_upgraded_default_gem
    omit "this test can't work under ruby-core setup" if ruby_repo?

    newer_json = util_spec("json", "999.99.9", nil, ["lib/json.rb"])
    install_gem newer_json

    path = "#{@tempdir}/test_realworld_upgraded_default_gem.rb"
    code = <<-RUBY
      $stderr = $stdout
      require "json"
      puts Gem.loaded_specs["json"].version
      puts $LOADED_FEATURES
    RUBY
    File.write(path, code)

    output = Gem::Util.popen({ 'GEM_HOME' => @gemhome }, *ruby_with_rubygems_in_load_path, path).strip
    assert $?.success?
    refute_empty output
    assert_equal "999.99.9", output.lines[0].chomp
    # Make sure only files from the newer json gem are loaded, and no files from the default json gem
    assert_equal ["#{@gemhome}/gems/json-999.99.9/lib/json.rb"], output.lines.grep(%r{/gems/json-}).map(&:chomp)
  end

  def test_default_gem_and_normal_gem
    default_gem_spec = new_default_spec("default", "2.0.0.0",
                                        nil, "default/gem.rb")
    install_default_gems(default_gem_spec)
    normal_gem_spec = util_spec("default", "3.0", nil,
                               "lib/default/gem.rb")
    install_specs(normal_gem_spec)
    assert_require "default/gem"
    assert_equal %w[default-3.0], loaded_spec_names
  end

  def test_normal_gems_with_overridden_load_error_message
    normal_gem_spec = util_spec("normal", "3.0", nil, "lib/normal/gem.rb")

    install_specs(normal_gem_spec)

    File.write("require_with_overridden_load_error_message.rb", <<-RUBY)
      LoadError.class_eval do
        def message
          "Overridden message"
        end
      end

      require 'normal/gem'
    RUBY

    require "open3"

    output, exit_status = Open3.capture2e(
      { "GEM_HOME" => Gem.paths.home },
      *ruby_with_rubygems_in_load_path,
      "-r",
      "./require_with_overridden_load_error_message.rb"
    )

    assert exit_status.success?, "Require failed due to #{output}"
  end

  def test_default_gem_prerelease
    default_gem_spec = new_default_spec("default", "2.0.0",
                                        nil, "default/gem.rb")
    install_default_gems(default_gem_spec)

    normal_gem_higher_prerelease_spec = util_spec("default", "3.0.0.rc2", nil,
                                                  "lib/default/gem.rb")
    install_default_gems(normal_gem_higher_prerelease_spec)

    assert_require "default/gem"
    assert_equal %w[default-3.0.0.rc2], loaded_spec_names
  end

  def loaded_spec_names
    Gem.loaded_specs.values.map(&:full_name).sort
  end

  def unresolved_names
    Gem::Specification.unresolved_deps.values.map(&:to_s).sort
  end

  def test_try_activate_error_unlocks_require_monitor
    silence_warnings do
      class << ::Gem
        alias old_try_activate try_activate
        def try_activate(*); raise 'raised from try_activate'; end
      end
    end

    require 'does_not_exist_for_try_activate_test'
  rescue RuntimeError => e
    assert_match(/raised from try_activate/, e.message)
    assert Kernel::RUBYGEMS_ACTIVATION_MONITOR.try_enter, "require monitor was not unlocked when try_activate raised"
  ensure
    silence_warnings do
      class << ::Gem
        alias try_activate old_try_activate
      end
    end
    Kernel::RUBYGEMS_ACTIVATION_MONITOR.exit
  end

  def test_require_when_gem_defined
    default_gem_spec = new_default_spec("default", "2.0.0.0",
                                        nil, "default/gem.rb")
    install_default_gems(default_gem_spec)
    c = Class.new do
      def self.gem(*args)
        raise "received #gem with #{args.inspect}"
      end
    end
    assert c.send(:require, "default/gem")
    assert_equal %w[default-2.0.0.0], loaded_spec_names
  end

  def test_require_default_when_gem_defined
    a = util_spec("a#{$$}", "1", nil, "lib/a#{$$}.rb")
    install_specs a
    c = Class.new do
      def self.gem(*args)
        raise "received #gem with #{args.inspect}"
      end
    end
    assert c.send(:require, "a#{$$}")
    assert_equal %W[a#{$$}-1], loaded_spec_names
  end

  def test_require_bundler
    b1 = util_spec('bundler', '1', nil, "lib/bundler/setup.rb")
    b2a = util_spec('bundler', '2.a', nil, "lib/bundler/setup.rb")
    install_specs b1, b2a

    require "rubygems/bundler_version_finder"
    $:.clear
    assert_require 'bundler/setup'
    assert_equal %w[bundler-2.a], loaded_spec_names
    assert_empty unresolved_names
  end

  # uplevel is 2.5+ only
  if RUBY_VERSION >= "2.5"
    ["", "Kernel."].each do |prefix|
      define_method "test_no_kernel_require_in_#{prefix.tr(".", "_")}warn_with_uplevel" do
        Dir.mktmpdir("warn_test") do |dir|
          File.write(dir + "/sub.rb", "#{prefix}warn 'uplevel', 'test', uplevel: 1\n")
          File.write(dir + "/main.rb", "require 'sub'\n")
          _, err = capture_subprocess_io do
            system(*ruby_with_rubygems_in_load_path, "-w", "--disable=gems", "-C", dir, "-I", dir, "main.rb")
          end
          assert_match(/main\.rb:1: warning: uplevel\ntest\n$/, err)
          _, err = capture_subprocess_io do
            system(*ruby_with_rubygems_in_load_path, "-w", "--enable=gems", "-C", dir, "-I", dir, "main.rb")
          end
          assert_match(/main\.rb:1: warning: uplevel\ntest\n$/, err)
        end
      end

      define_method "test_no_other_behavioral_changes_with_#{prefix.tr(".", "_")}warn" do
        Dir.mktmpdir("warn_test") do |dir|
          File.write(dir + "/main.rb", "#{prefix}warn({x:1}, {y:2}, [])\n")
          _, err = capture_subprocess_io do
            system(*ruby_with_rubygems_in_load_path, "-w", "--disable=gems", "-C", dir, "main.rb")
          end
          assert_match(/{:x=>1}\n{:y=>2}\n$/, err)
          _, err = capture_subprocess_io do
            system(*ruby_with_rubygems_in_load_path, "-w", "--enable=gems", "-C", dir, "main.rb")
          end
          assert_match(/{:x=>1}\n{:y=>2}\n$/, err)
        end
      end
    end

    def test_no_crash_when_overriding_warn_with_warning_module
      Dir.mktmpdir("warn_test") do |dir|
        File.write(dir + "/main.rb", "module Warning; def warn(str); super; end; end; warn 'Foo Bar'")
        _, err = capture_subprocess_io do
          system(*ruby_with_rubygems_in_load_path, "-w", "--disable=gems", "-C", dir, "main.rb")
        end
        assert_match(/Foo Bar\n$/, err)
        _, err = capture_subprocess_io do
          system(*ruby_with_rubygems_in_load_path, "-w", "--enable=gems", "-C", dir, "main.rb")
        end
        assert_match(/Foo Bar\n$/, err)
      end
    end

    def test_expected_backtrace_location_when_inheriting_from_basic_object_and_including_kernel
      Dir.mktmpdir("warn_test") do |dir|
        File.write(dir + "/main.rb", "\nrequire 'sub'\n")
        File.write(dir + "/sub.rb", <<-'RUBY')
          require 'rubygems'
          class C < BasicObject
            include ::Kernel
            def deprecated
              warn "This is a deprecated method", uplevel: 2
            end
          end
          C.new.deprecated
        RUBY

        _, err = capture_subprocess_io do
          system(*ruby_with_rubygems_in_load_path, "-w", "--disable=gems", "-C", dir, "-I", dir, "main.rb")
        end
        assert_match(/main\.rb:2: warning: This is a deprecated method$/, err)
        _, err = capture_subprocess_io do
          system(*ruby_with_rubygems_in_load_path, "-w", "--enable=gems", "-C", dir, "-I", dir, "main.rb")
        end
        assert_match(/main\.rb:2: warning: This is a deprecated method$/, err)
      end
    end
  end

  private

  def util_install_extension_file(name)
    spec = quick_gem name
    util_build_gem spec

    spec.extensions << "extconf.rb"
    write_file File.join(@tempdir, "extconf.rb") do |io|
      io.write <<-RUBY
        require "mkmf"
        CONFIG['LDSHARED'] = '$(TOUCH) $@ ||'
        create_makefile("#{name}")
      RUBY
    end

    write_file File.join(@tempdir, "#{name}.c") do |io|
      io.write <<-C
        void Init_#{name}() { }
      C
    end

    write_file File.join(@tempdir, "depend")

    spec.files += ["extconf.rb", "depend", "#{name}.c"]

    so = File.join(spec.gem_dir, "#{name}.#{RbConfig::CONFIG["DLEXT"]}")
    assert_path_not_exist so

    path = Gem::Package.build spec
    installer = Gem::Installer.at path
    installer.install
    assert_path_exist so

    spec.gem_dir
  end

  def util_install_ruby_file(name)
    dir_lib = Dir.mktmpdir("test_require_lib", @tempdir)
    dash_i_lib_arg = File.join dir_lib

    a_rb = File.join dash_i_lib_arg, "#{name}.rb"

    FileUtils.mkdir_p File.dirname a_rb
    File.open(a_rb, 'w') {|f| f.write "# #{name}.rb" }

    dash_i_lib_arg
  end
end