diff --git a/lib/bundler.rb b/lib/bundler.rb
index 0025dee720..47b352177d 100644
--- a/lib/bundler.rb
+++ b/lib/bundler.rb
@@ -370,7 +370,7 @@ EOF
 
       if env.key?("RUBYLIB")
         rubylib = env["RUBYLIB"].split(File::PATH_SEPARATOR)
-        rubylib.delete(File.expand_path("..", __FILE__))
+        rubylib.delete(__dir__)
         env["RUBYLIB"] = rubylib.join(File::PATH_SEPARATOR)
       end
 
diff --git a/lib/bundler/build_metadata.rb b/lib/bundler/build_metadata.rb
index 0846e82e06..8bffb2fae7 100644
--- a/lib/bundler/build_metadata.rb
+++ b/lib/bundler/build_metadata.rb
@@ -27,7 +27,7 @@ module Bundler
 
       # If Bundler has been installed without its .git directory and without a
       # commit instance variable then we can't determine its commits SHA.
-      git_dir = File.join(File.expand_path("../../../..", __FILE__), ".git")
+      git_dir = File.expand_path("../../../.git", __dir__)
       if File.directory?(git_dir)
         return @git_commit_sha = Dir.chdir(git_dir) { `git rev-parse --short HEAD`.strip.freeze }
       end
diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 922ba469a4..e1c284130b 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -610,7 +610,7 @@ module Bundler
     private :gem
 
     def self.source_root
-      File.expand_path(File.join(File.dirname(__FILE__), "templates"))
+      File.expand_path("templates", __dir__)
     end
 
     desc "clean [OPTIONS]", "Cleans up unused gems in your bundler directory", :hide => true
diff --git a/lib/bundler/cli/info.rb b/lib/bundler/cli/info.rb
index 38bc008cb5..0545ce8c75 100644
--- a/lib/bundler/cli/info.rb
+++ b/lib/bundler/cli/info.rb
@@ -47,7 +47,7 @@ module Bundler
     def print_gem_path(spec)
       name = spec.name
       if name == "bundler"
-        path = File.expand_path("../../../..", __FILE__)
+        path = File.expand_path("../../..", __dir__)
       else
         path = spec.full_gem_path
         if spec.deleted_gem?
diff --git a/lib/bundler/cli/init.rb b/lib/bundler/cli/init.rb
index d851d02d42..e4f8229c48 100644
--- a/lib/bundler/cli/init.rb
+++ b/lib/bundler/cli/init.rb
@@ -32,7 +32,7 @@ module Bundler
           file << spec.to_gemfile
         end
       else
-        FileUtils.cp(File.expand_path("../../templates/#{gemfile}", __FILE__), gemfile)
+        FileUtils.cp(File.expand_path("../templates/#{gemfile}", __dir__), gemfile)
       end
 
       puts "Writing new #{gemfile} to #{SharedHelpers.pwd}/#{gemfile}"
diff --git a/lib/bundler/cli/show.rb b/lib/bundler/cli/show.rb
index 5eaaba1ef7..2df13db1fa 100644
--- a/lib/bundler/cli/show.rb
+++ b/lib/bundler/cli/show.rb
@@ -18,7 +18,7 @@ module Bundler
 
       if gem_name
         if gem_name == "bundler"
-          path = File.expand_path("../../../..", __FILE__)
+          path = File.expand_path("../../..", __dir__)
         else
           spec = Bundler::CLI::Common.select_spec(gem_name, :regex_match)
           return unless spec
diff --git a/lib/bundler/installer.rb b/lib/bundler/installer.rb
index 61bf1e06d4..ca9df4a21e 100644
--- a/lib/bundler/installer.rb
+++ b/lib/bundler/installer.rb
@@ -119,7 +119,7 @@ module Bundler
       relative_gemfile_path = relative_gemfile_path
       ruby_command = Thor::Util.ruby_command
       ruby_command = ruby_command
-      template_path = File.expand_path("../templates/Executable", __FILE__)
+      template_path = File.expand_path("templates/Executable", __dir__)
       if spec.name == "bundler"
         template_path += ".bundler"
         spec.executables = %(bundle)
@@ -172,7 +172,7 @@ module Bundler
       end
       standalone_path = Bundler.root.join(path).relative_path_from(bin_path)
       standalone_path = standalone_path
-      template = File.read(File.expand_path("../templates/Executable.standalone", __FILE__))
+      template = File.read(File.expand_path("templates/Executable.standalone", __dir__))
       ruby_command = Thor::Util.ruby_command
       ruby_command = ruby_command
 
diff --git a/lib/bundler/shared_helpers.rb b/lib/bundler/shared_helpers.rb
index ed0b072b65..ffdbdee503 100644
--- a/lib/bundler/shared_helpers.rb
+++ b/lib/bundler/shared_helpers.rb
@@ -274,10 +274,10 @@ module Bundler
 
     def set_bundle_variables
       # bundler exe & lib folders have same root folder, typical gem installation
-      exe_file = File.expand_path("../../../exe/bundle", __FILE__)
+      exe_file = File.expand_path("../../exe/bundle", __dir__)
 
       # for Ruby core repository testing
-      exe_file = File.expand_path("../../../libexec/bundle", __FILE__) unless File.exist?(exe_file)
+      exe_file = File.expand_path("../../libexec/bundle", __dir__) unless File.exist?(exe_file)
 
       # bundler is a default gem, exe path is separate
       exe_file = Bundler.rubygems.bin_path("bundler", "bundle", VERSION) unless File.exist?(exe_file)
@@ -309,7 +309,7 @@ module Bundler
     end
 
     def bundler_ruby_lib
-      resolve_path File.expand_path("../..", __FILE__)
+      File.expand_path("..", __dir__)
     end
 
     def clean_load_path
diff --git a/lib/bundler/source/metadata.rb b/lib/bundler/source/metadata.rb
index 8bdbaa5527..524afd750a 100644
--- a/lib/bundler/source/metadata.rb
+++ b/lib/bundler/source/metadata.rb
@@ -22,7 +22,7 @@ module Bundler
             s.summary  = "The best way to manage your application's dependencies"
             s.executables = %w[bundle]
             # can't point to the actual gemspec or else the require paths will be wrong
-            s.loaded_from = File.expand_path("..", __FILE__)
+            s.loaded_from = __dir__
           end
 
           if local_spec = Bundler.rubygems.find_bundler(VERSION)
diff --git a/lib/bundler/templates/Executable b/lib/bundler/templates/Executable
index 3e8d5b317a..f6487e3c89 100644
--- a/lib/bundler/templates/Executable
+++ b/lib/bundler/templates/Executable
@@ -8,11 +8,9 @@
 # this file is here to facilitate running it.
 #
 
-require "pathname"
-ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../<%= relative_gemfile_path %>",
-  Pathname.new(__FILE__).realpath)
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("<%= relative_gemfile_path %>", __dir__)
 
-bundle_binstub = File.expand_path("../bundle", __FILE__)
+bundle_binstub = File.expand_path("bundle", __dir__)
 
 if File.file?(bundle_binstub)
   if File.read(bundle_binstub, 300) =~ /This file was generated by Bundler/
diff --git a/lib/bundler/templates/Executable.bundler b/lib/bundler/templates/Executable.bundler
index 6bb5c51090..51650c7664 100644
--- a/lib/bundler/templates/Executable.bundler
+++ b/lib/bundler/templates/Executable.bundler
@@ -41,7 +41,7 @@ m = Module.new do
     gemfile = ENV["BUNDLE_GEMFILE"]
     return gemfile if gemfile && !gemfile.empty?
 
-    File.expand_path("../<%= relative_gemfile_path %>", __FILE__)
+    File.expand_path("<%= relative_gemfile_path %>", __dir__)
   end
 
   def lockfile
diff --git a/lib/bundler/templates/Executable.standalone b/lib/bundler/templates/Executable.standalone
index 4bf0753f44..d591e3fc04 100644
--- a/lib/bundler/templates/Executable.standalone
+++ b/lib/bundler/templates/Executable.standalone
@@ -6,9 +6,7 @@
 # this file is here to facilitate running it.
 #
 
-require "pathname"
-path = Pathname.new(__FILE__)
-$:.unshift File.expand_path "../<%= standalone_path %>", path.realpath
+$:.unshift File.expand_path "<%= standalone_path %>", __dir__
 
 require "bundler/setup"
-load File.expand_path "../<%= executable_path %>", path.realpath
+load File.expand_path "<%= executable_path %>", __dir__
diff --git a/lib/bundler/templates/newgem/newgem.gemspec.tt b/lib/bundler/templates/newgem/newgem.gemspec.tt
index 546a28b78a..ceb2e9b28d 100644
--- a/lib/bundler/templates/newgem/newgem.gemspec.tt
+++ b/lib/bundler/templates/newgem/newgem.gemspec.tt
@@ -24,7 +24,7 @@ Gem::Specification.new do |spec|
 
   # Specify which files should be added to the gem when it is released.
   # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
-  spec.files = Dir.chdir(File.expand_path(__dir__)) do
+  spec.files = Dir.chdir(__dir__) do
     `git ls-files -z`.split("\x0").reject do |f|
       (f == __FILE__) || f.match(%r{\A(?:(?:bin|test|spec|features)/|\.(?:git|travis|circleci)|appveyor)})
     end
diff --git a/lib/rubygems.rb b/lib/rubygems.rb
index 1f706b004f..d2c404d7d3 100644
--- a/lib/rubygems.rb
+++ b/lib/rubygems.rb
@@ -112,7 +112,7 @@ require_relative 'rubygems/errors'
 # -The RubyGems Team
 
 module Gem
-  RUBYGEMS_DIR = File.dirname File.expand_path(__FILE__)
+  RUBYGEMS_DIR = __dir__
 
   # Taint support is deprecated in Ruby 2.7.
   # This allows switching ".untaint" to ".tap(&Gem::UNTAINT)",
diff --git a/lib/rubygems/commands/setup_command.rb b/lib/rubygems/commands/setup_command.rb
index 01714f0342..7b6890013c 100644
--- a/lib/rubygems/commands/setup_command.rb
+++ b/lib/rubygems/commands/setup_command.rb
@@ -341,7 +341,7 @@ By default, this RubyGems will install gem as:
 
       fake_spec = Gem::Specification.new 'rubygems', Gem::VERSION
       def fake_spec.full_gem_path
-        File.expand_path '../../../..', __FILE__
+        File.expand_path '../../..', __dir__
       end
 
       generate_ri   = options[:document].include? 'ri'
diff --git a/lib/rubygems/ext/ext_conf_builder.rb b/lib/rubygems/ext/ext_conf_builder.rb
index 3ca3463615..3e8aa950c9 100644
--- a/lib/rubygems/ext/ext_conf_builder.rb
+++ b/lib/rubygems/ext/ext_conf_builder.rb
@@ -39,7 +39,7 @@ class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
         # workaround for https://github.com/oracle/truffleruby/issues/2115
         siteconf_path = RUBY_ENGINE == "truffleruby" ? siteconf.path.dup : siteconf.path
         require "shellwords"
-        cmd = Gem.ruby.shellsplit << "-I" << File.expand_path("../../..", __FILE__) <<
+        cmd = Gem.ruby.shellsplit << "-I" << File.expand_path('../..', __dir__) <<
               "-r" << get_relative_path(siteconf_path, extension_dir) << File.basename(extension)
         cmd.push(*args)
 
diff --git a/lib/rubygems/request.rb b/lib/rubygems/request.rb
index d6100c914b..136b154bee 100644
--- a/lib/rubygems/request.rb
+++ b/lib/rubygems/request.rb
@@ -39,7 +39,7 @@ class Gem::Request
   def cert_files; @connection_pool.cert_files; end
 
   def self.get_cert_files
-    pattern = File.expand_path("./ssl_certs/*/*.pem", File.dirname(__FILE__))
+    pattern = File.expand_path("./ssl_certs/*/*.pem", __dir__)
     Dir.glob(pattern)
   end
 
diff --git a/libexec/bundler b/libexec/bundler
index d9131fe834..a6826a8c89 100755
--- a/libexec/bundler
+++ b/libexec/bundler
@@ -1,4 +1,4 @@
 #!/usr/bin/env ruby
 # frozen_string_literal: true
 
-load File.expand_path("../bundle", __FILE__)
+load File.expand_path("bundle", __dir__)
diff --git a/spec/bundler/commands/install_spec.rb b/spec/bundler/commands/install_spec.rb
index 9e06c51a08..f189a70b10 100644
--- a/spec/bundler/commands/install_spec.rb
+++ b/spec/bundler/commands/install_spec.rb
@@ -798,7 +798,7 @@ RSpec.describe "bundle install with gem sources" do
     it "includes the standalone path" do
       bundle "binstubs rack", :standalone => true
       standalone_line = File.read(bundled_app("bin/rackup")).each_line.find {|line| line.include? "$:.unshift" }.strip
-      expect(standalone_line).to eq %($:.unshift File.expand_path "../../bundle", path.realpath)
+      expect(standalone_line).to eq %($:.unshift File.expand_path "../bundle", __dir__)
     end
   end
 
diff --git a/spec/bundler/commands/update_spec.rb b/spec/bundler/commands/update_spec.rb
index ee5d53c527..d013d5bd73 100644
--- a/spec/bundler/commands/update_spec.rb
+++ b/spec/bundler/commands/update_spec.rb
@@ -1147,7 +1147,7 @@ RSpec.describe "bundle update --bundler" do
   end
 
   it "updates the bundler version in the lockfile without re-resolving if the highest version is already installed" do
-    system_gems "bundler-2.3.3"
+    system_gems "bundler-2.3.9"
 
     build_repo4 do
       build_gem "rack", "1.0"
@@ -1157,7 +1157,7 @@ RSpec.describe "bundle update --bundler" do
       source "#{file_uri_for(gem_repo4)}"
       gem "rack"
     G
-    lockfile lockfile.sub(/(^\s*)#{Bundler::VERSION}($)/, "2.3.3")
+    lockfile lockfile.sub(/(^\s*)#{Bundler::VERSION}($)/, "2.3.9")
 
     bundle :update, :bundler => true, :artifice => "compact_index", :verbose => true
     expect(out).to include("Using bundler #{Bundler::VERSION}")
@@ -1182,7 +1182,7 @@ RSpec.describe "bundle update --bundler" do
   end
 
   it "updates the bundler version in the lockfile even if the latest version is not installed", :ruby_repo, :realworld do
-    pristine_system_gems "bundler-2.3.3"
+    pristine_system_gems "bundler-2.3.9"
 
     build_repo4 do
       build_gem "rack", "1.0"
@@ -1192,16 +1192,16 @@ RSpec.describe "bundle update --bundler" do
       source "#{file_uri_for(gem_repo4)}"
       gem "rack"
     G
-    lockfile lockfile.sub(/(^\s*)#{Bundler::VERSION}($)/, "2.3.3")
+    lockfile lockfile.sub(/(^\s*)#{Bundler::VERSION}($)/, "2.3.9")
 
     bundle :update, :bundler => true, :artifice => "vcr", :verbose => true
 
     # Only updates properly on modern RubyGems.
 
     if Gem.rubygems_version >= Gem::Version.new("3.3.0.dev")
-      expect(out).to include("Updating bundler to 2.3.4")
-      expect(out).to include("Using bundler 2.3.4")
-      expect(out).not_to include("Installing Bundler 2.3.3 and restarting using that version.")
+      expect(out).to include("Updating bundler to 2.3.10")
+      expect(out).to include("Using bundler 2.3.10")
+      expect(out).not_to include("Installing Bundler 2.3.9 and restarting using that version.")
 
       expect(lockfile).to eq <<~L
         GEM
@@ -1216,17 +1216,17 @@ RSpec.describe "bundle update --bundler" do
           rack
 
         BUNDLED WITH
-           2.3.4
+           2.3.10
       L
 
-      expect(the_bundle).to include_gems "bundler 2.3.4"
+      expect(the_bundle).to include_gems "bundler 2.3.10"
     end
 
     expect(the_bundle).to include_gems "rack 1.0"
   end
 
   it "errors if the explicit target version does not exist", :realworld do
-    pristine_system_gems "bundler-2.3.3"
+    pristine_system_gems "bundler-2.3.9"
 
     build_repo4 do
       build_gem "rack", "1.0"
@@ -1236,7 +1236,7 @@ RSpec.describe "bundle update --bundler" do
       source "#{file_uri_for(gem_repo4)}"
       gem "rack"
     G
-    lockfile lockfile.sub(/(^\s*)#{Bundler::VERSION}($)/, "2.3.3")
+    lockfile lockfile.sub(/(^\s*)#{Bundler::VERSION}($)/, "2.3.9")
 
     bundle :update, :bundler => "999.999.999", :artifice => "vcr", :raise_on_error => false
 
@@ -1286,7 +1286,7 @@ RSpec.describe "bundle update --bundler" do
   end
 
   it "does not touch the network if not necessary" do
-    system_gems "bundler-2.3.3"
+    system_gems "bundler-2.3.9"
 
     build_repo4 do
       build_gem "rack", "1.0"
@@ -1297,7 +1297,7 @@ RSpec.describe "bundle update --bundler" do
       gem "rack"
     G
 
-    bundle :update, :bundler => "2.3.3", :raise_on_error => false
+    bundle :update, :bundler => "2.3.9", :raise_on_error => false
 
     expect(out).not_to include("Fetching gem metadata from https://rubygems.org/")
 
@@ -1317,10 +1317,10 @@ RSpec.describe "bundle update --bundler" do
           rack
 
         BUNDLED WITH
-           2.3.3
+           2.3.9
       L
 
-      expect(out).to include("Using bundler 2.3.3")
+      expect(out).to include("Using bundler 2.3.9")
     end
   end
 end
diff --git a/spec/bundler/install/gemfile/git_spec.rb b/spec/bundler/install/gemfile/git_spec.rb
index 365a84f39e..07995d013b 100644
--- a/spec/bundler/install/gemfile/git_spec.rb
+++ b/spec/bundler/install/gemfile/git_spec.rb
@@ -1180,7 +1180,7 @@ RSpec.describe "bundle install with git sources" do
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             File.open("\#{path}/foo.rb", "w") do |f|
               f.puts "FOO = 'YES'"
@@ -1273,7 +1273,7 @@ In Gemfile:
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             cur_time = Time.now.to_f.to_s
             File.open("\#{path}/foo.rb", "w") do |f|
@@ -1314,7 +1314,7 @@ In Gemfile:
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             cur_time = Time.now.to_f.to_s
             File.open("\#{path}/foo.rb", "w") do |f|
@@ -1357,7 +1357,7 @@ In Gemfile:
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             cur_time = Time.now.to_f.to_s
             File.open("\#{path}/foo.rb", "w") do |f|
diff --git a/spec/bundler/install/gemfile/path_spec.rb b/spec/bundler/install/gemfile/path_spec.rb
index bea7c11dec..515901064f 100644
--- a/spec/bundler/install/gemfile/path_spec.rb
+++ b/spec/bundler/install/gemfile/path_spec.rb
@@ -137,7 +137,7 @@ RSpec.describe "bundle install with explicit source paths" do
 
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
-      gem 'foo', :path => File.expand_path("../foo-1.0", __FILE__)
+      gem 'foo', :path => File.expand_path("foo-1.0", __dir__)
     G
 
     bundle "config set --local frozen true"
diff --git a/spec/bundler/install/gems/compact_index_spec.rb b/spec/bundler/install/gems/compact_index_spec.rb
index 1282dbf381..72ad40e24f 100644
--- a/spec/bundler/install/gems/compact_index_spec.rb
+++ b/spec/bundler/install/gems/compact_index_spec.rb
@@ -258,7 +258,7 @@ The checksum of /versions does not match the checksum provided by the server! So
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             File.open("\#{path}/net_build_extensions.rb", "w") do |f|
               f.puts "NET_BUILD_EXTENSIONS = 'YES'"
diff --git a/spec/bundler/install/gems/resolving_spec.rb b/spec/bundler/install/gems/resolving_spec.rb
index b0209489b9..209996f61f 100644
--- a/spec/bundler/install/gems/resolving_spec.rb
+++ b/spec/bundler/install/gems/resolving_spec.rb
@@ -7,7 +7,7 @@ RSpec.describe "bundle install with install-time dependencies" do
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             File.open("\#{path}/implicit_rake_dep.rb", "w") do |f|
               f.puts "IMPLICIT_RAKE_DEP = 'YES'"
@@ -20,7 +20,7 @@ RSpec.describe "bundle install with install-time dependencies" do
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             File.open("\#{path}/another_implicit_rake_dep.rb", "w") do |f|
               f.puts "ANOTHER_IMPLICIT_RAKE_DEP = 'YES'"
@@ -42,7 +42,7 @@ RSpec.describe "bundle install with install-time dependencies" do
         s.extensions << "Rakefile"
         s.write "Rakefile", <<-RUBY
           task :default do
-            path = File.expand_path("../lib", __FILE__)
+            path = File.expand_path("lib", __dir__)
             FileUtils.mkdir_p(path)
             File.open("\#{path}/net_build_extensions.rb", "w") do |f|
               f.puts "NET_BUILD_EXTENSIONS = 'YES'"
diff --git a/spec/bundler/install/gems/standalone_spec.rb b/spec/bundler/install/gems/standalone_spec.rb
index c7efc836a8..66dd7f534a 100644
--- a/spec/bundler/install/gems/standalone_spec.rb
+++ b/spec/bundler/install/gems/standalone_spec.rb
@@ -205,7 +205,7 @@ RSpec.shared_examples "bundle install --standalone" do
       build_git "bar", :gemspec => false do |s|
         s.write "lib/bar/version.rb", %(BAR_VERSION = '1.0')
         s.write "bar.gemspec", <<-G
-          lib = File.expand_path('../lib/', __FILE__)
+          lib = File.expand_path('lib/', __dir__)
           $:.unshift lib unless $:.include?(lib)
           require 'bar/version'
 
@@ -419,7 +419,7 @@ RSpec.shared_examples "bundle install --standalone" do
 
     it "creates stubs with the correct load path" do
       extension_line = File.read(bundled_app("bin/rails")).each_line.find {|line| line.include? "$:.unshift" }.strip
-      expect(extension_line).to eq %($:.unshift File.expand_path "../../bundle", path.realpath)
+      expect(extension_line).to eq %($:.unshift File.expand_path "../bundle", __dir__)
     end
   end
 end
diff --git a/spec/bundler/install/gems/sudo_spec.rb b/spec/bundler/install/gems/sudo_spec.rb
index 3e5d38ea4c..41b241da25 100644
--- a/spec/bundler/install/gems/sudo_spec.rb
+++ b/spec/bundler/install/gems/sudo_spec.rb
@@ -54,7 +54,7 @@ RSpec.describe "when using sudo", :sudo => true do
           s.extensions << "Rakefile"
           s.write "Rakefile", <<-RUBY
             task :default do
-              path = File.expand_path("../lib", __FILE__)
+              path = File.expand_path("lib", __dir__)
               FileUtils.mkdir_p(path)
               File.open("\#{path}/another_implicit_rake_dep.rb", "w") do |f|
                 f.puts "ANOTHER_IMPLICIT_RAKE_DEP = 'YES'"
diff --git a/spec/bundler/lock/lockfile_spec.rb b/spec/bundler/lock/lockfile_spec.rb
index 561de9f3bc..8ec0a80bd0 100644
--- a/spec/bundler/lock/lockfile_spec.rb
+++ b/spec/bundler/lock/lockfile_spec.rb
@@ -897,7 +897,7 @@ RSpec.describe "the lockfile format" do
 
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
-      path File.expand_path("../foo", __FILE__) do
+      path File.expand_path("foo", __dir__) do
         gem "foo"
       end
     G
diff --git a/test/rubygems/helper.rb b/test/rubygems/helper.rb
index 5ed51fec10..be9016b831 100644
--- a/test/rubygems/helper.rb
+++ b/test/rubygems/helper.rb
@@ -3,7 +3,7 @@
 require 'rubygems'
 
 # If bundler gemspec exists, add to stubs
-bundler_gemspec = File.expand_path("../../../bundler/bundler.gemspec", __FILE__)
+bundler_gemspec = File.expand_path('../../bundler/bundler.gemspec', __dir__)
 if File.exist?(bundler_gemspec)
   Gem::Specification.dirs.unshift File.dirname(bundler_gemspec)
   Gem::Specification.class_variable_set :@@stubs, nil
diff --git a/test/rubygems/test_gem.rb b/test/rubygems/test_gem.rb
index cc4772a0c6..a8be078046 100644
--- a/test/rubygems/test_gem.rb
+++ b/test/rubygems/test_gem.rb
@@ -10,7 +10,7 @@ require 'rbconfig'
 class TestGem < Gem::TestCase
   PLUGINS_LOADED = [] # rubocop:disable Style/MutableConstant
 
-  PROJECT_DIR = File.expand_path('../../..', __FILE__).tap(&Gem::UNTAINT)
+  PROJECT_DIR = File.expand_path('../..', __dir__).tap(&Gem::UNTAINT)
 
   def setup
     super
diff --git a/test/rubygems/test_gem_command_manager.rb b/test/rubygems/test_gem_command_manager.rb
index ff1f955c6c..bee635d67e 100644
--- a/test/rubygems/test_gem_command_manager.rb
+++ b/test/rubygems/test_gem_command_manager.rb
@@ -3,7 +3,7 @@ require_relative 'helper'
 require 'rubygems/command_manager'
 
 class TestGemCommandManager < Gem::TestCase
-  PROJECT_DIR = File.expand_path('../../..', __FILE__).tap(&Gem::UNTAINT)
+  PROJECT_DIR = File.expand_path('../..', __dir__).tap(&Gem::UNTAINT)
 
   def setup
     super
diff --git a/test/rubygems/test_gem_commands_help_command.rb b/test/rubygems/test_gem_commands_help_command.rb
index a70dd770e1..98e5b62be0 100644
--- a/test/rubygems/test_gem_commands_help_command.rb
+++ b/test/rubygems/test_gem_commands_help_command.rb
@@ -11,7 +11,7 @@ class TestGemCommandsHelpCommand < Gem::TestCase
 
     @cmd = Gem::Commands::HelpCommand.new
 
-    load File.expand_path('../rubygems_plugin.rb', __FILE__) unless Gem::Commands.const_defined? :InterruptCommand
+    load File.expand_path('rubygems_plugin.rb', __dir__) unless Gem::Commands.const_defined? :InterruptCommand
   end
 
   def test_gem_help_bad
diff --git a/test/rubygems/test_gem_commands_setup_command.rb b/test/rubygems/test_gem_commands_setup_command.rb
index 934c76b1d1..ab563b28ee 100644
--- a/test/rubygems/test_gem_commands_setup_command.rb
+++ b/test/rubygems/test_gem_commands_setup_command.rb
@@ -4,7 +4,7 @@ require_relative 'helper'
 require 'rubygems/commands/setup_command'
 
 class TestGemCommandsSetupCommand < Gem::TestCase
-  bundler_gemspec = File.expand_path("../../../bundler/lib/bundler/version.rb", __FILE__)
+  bundler_gemspec = File.expand_path('../../bundler/lib/bundler/version.rb', __dir__)
   if File.exist?(bundler_gemspec)
     BUNDLER_VERS = File.read(bundler_gemspec).match(/VERSION = "(#{Gem::Version::VERSION_PATTERN})"/)[1]
   else
diff --git a/test/rubygems/test_gem_dependency_installer.rb b/test/rubygems/test_gem_dependency_installer.rb
index 9cbdcefea4..f2404d61c7 100644
--- a/test/rubygems/test_gem_dependency_installer.rb
+++ b/test/rubygems/test_gem_dependency_installer.rb
@@ -941,7 +941,7 @@ class TestGemDependencyInstaller < Gem::TestCase
   end
 
   def test_install_legacy_spec_with_nil_required_ruby_version
-    path = File.expand_path "../data/null-required-ruby-version.gemspec.rz", __FILE__
+    path = File.expand_path 'data/null-required-ruby-version.gemspec.rz', __dir__
     spec = Marshal.load Gem.read_binary(path)
     def spec.validate(*args); end
 
@@ -966,7 +966,7 @@ class TestGemDependencyInstaller < Gem::TestCase
   end
 
   def test_install_legacy_spec_with_nil_required_rubygems_version
-    path = File.expand_path "../data/null-required-rubygems-version.gemspec.rz", __FILE__
+    path = File.expand_path 'data/null-required-rubygems-version.gemspec.rz', __dir__
     spec = Marshal.load Gem.read_binary(path)
     def spec.validate(*args); end
 
diff --git a/test/rubygems/test_gem_ext_builder.rb b/test/rubygems/test_gem_ext_builder.rb
index 165194510e..7e19782e61 100644
--- a/test/rubygems/test_gem_ext_builder.rb
+++ b/test/rubygems/test_gem_ext_builder.rb
@@ -291,7 +291,7 @@ install:
     File.open File.join(@spec.gem_dir, "extconf.rb"), "w" do |f|
       f.write <<-'RUBY'
         puts "IN EXTCONF"
-        extconf_args = File.join File.dirname(__FILE__), 'extconf_args'
+        extconf_args = File.join __dir__, 'extconf_args'
         File.open extconf_args, 'w' do |f|
           f.puts ARGV.inspect
         end
diff --git a/test/rubygems/test_gem_ext_cargo_builder.rb b/test/rubygems/test_gem_ext_cargo_builder.rb
index 5a1c035947..0c8de2ff6c 100644
--- a/test/rubygems/test_gem_ext_cargo_builder.rb
+++ b/test/rubygems/test_gem_ext_cargo_builder.rb
@@ -20,7 +20,7 @@ class TestGemExtCargoBuilder < Gem::TestCase
   def setup_rust_gem(name)
     @ext = File.join(@tempdir, 'ext')
     @dest_path = File.join(@tempdir, 'prefix')
-    @fixture_dir = Pathname.new(File.expand_path("../test_gem_ext_cargo_builder/#{name}/", __FILE__))
+    @fixture_dir = Pathname.new(File.expand_path("test_gem_ext_cargo_builder/#{name}/", __dir__))
 
     FileUtils.mkdir_p @dest_path
     FileUtils.cp_r(@fixture_dir.to_s, @ext)
@@ -103,7 +103,7 @@ class TestGemExtCargoBuilder < Gem::TestCase
     Dir.chdir @ext do
       require 'tmpdir'
 
-      gem = [@rust_envs, *ruby_with_rubygems_in_load_path, File.expand_path("./../../../bin/gem", __FILE__)]
+      gem = [@rust_envs, *ruby_with_rubygems_in_load_path, File.expand_path('../../bin/gem', __dir__)]
 
       Dir.mktmpdir("rust_ruby_example") do |dir|
         built_gem = File.expand_path(File.join(dir, "rust_ruby_example.gem"))
@@ -125,7 +125,7 @@ class TestGemExtCargoBuilder < Gem::TestCase
     Dir.chdir @ext do
       require 'tmpdir'
 
-      gem = [@rust_envs, *ruby_with_rubygems_in_load_path, File.expand_path("./../../../bin/gem", __FILE__)]
+      gem = [@rust_envs, *ruby_with_rubygems_in_load_path, File.expand_path('../../bin/gem', __dir__)]
 
       Dir.mktmpdir("custom_name") do |dir|
         built_gem = File.expand_path(File.join(dir, "custom_name.gem"))
diff --git a/test/rubygems/test_gem_ext_cargo_builder/custom_name/build.rb b/test/rubygems/test_gem_ext_cargo_builder/custom_name/build.rb
index a521dceb4a..4d2f8488a4 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/custom_name/build.rb
+++ b/test/rubygems/test_gem_ext_cargo_builder/custom_name/build.rb
@@ -9,9 +9,9 @@ end
 
 require 'tmpdir'
 
-lp = File.expand_path("./../../../../../lib", __FILE__)
-gem = ["ruby", "-I#{lp}", File.expand_path("./../../../../../bin/gem", __FILE__)]
-gemspec = File.expand_path("./../custom_name.gemspec", __FILE__)
+lp = File.expand_path('../../../../lib', __dir__)
+gem = ["ruby", "-I#{lp}", File.expand_path('../../../../bin/gem', __dir__)]
+gemspec = File.expand_path('custom_name.gemspec', __dir__)
 
 Dir.mktmpdir("custom_name") do |dir|
   built_gem = File.expand_path(File.join(dir, "custom_name.gem"))
diff --git a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/build.rb b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/build.rb
index 468274c9a7..da9e82315e 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/build.rb
+++ b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/build.rb
@@ -9,9 +9,9 @@ end
 
 require 'tmpdir'
 
-lp = File.expand_path("./../../../../../lib", __FILE__)
-gem = ["ruby", "-I#{lp}", File.expand_path("./../../../../../bin/gem", __FILE__)]
-gemspec = File.expand_path("./../rust_ruby_example.gemspec", __FILE__)
+lp = File.expand_path('../../../../lib', __dir__)
+gem = ["ruby", "-I#{lp}", File.expand_path('../../../../bin/gem', __dir__)]
+gemspec = File.expand_path('rust_ruby_example.gemspec', __dir__)
 
 Dir.mktmpdir("rust_ruby_example") do |dir|
   built_gem = File.expand_path(File.join(dir, "rust_ruby_example.gem"))
diff --git a/test/rubygems/test_gem_specification.rb b/test/rubygems/test_gem_specification.rb
index 8b4a07d23b..55dd7f0ff2 100644
--- a/test/rubygems/test_gem_specification.rb
+++ b/test/rubygems/test_gem_specification.rb
@@ -1068,7 +1068,7 @@ dependencies: []
   end
 
   def test_handles_private_null_type
-    path = File.expand_path "../data/null-type.gemspec.rz", __FILE__
+    path = File.expand_path 'data/null-type.gemspec.rz', __dir__
 
     data = Marshal.load Gem::Util.inflate(Gem.read_binary(path))
 
diff --git a/test/rubygems/test_project_sanity.rb b/test/rubygems/test_project_sanity.rb
index 38c2541df6..27b1f11d62 100644
--- a/test/rubygems/test_project_sanity.rb
+++ b/test/rubygems/test_project_sanity.rb
@@ -5,7 +5,7 @@ require "open3"
 
 class TestProjectSanity < Gem::TestCase
   def test_manifest_is_up_to_date
-    pend unless File.exist?(File.expand_path("../../../Rakefile", __FILE__))
+    pend unless File.exist?(File.expand_path('../../Rakefile', __dir__))
 
     _, status = Open3.capture2e("rake check_manifest")
 
diff --git a/test/rubygems/test_require.rb b/test/rubygems/test_require.rb
index 5b826d052b..90b943dff3 100644
--- a/test/rubygems/test_require.rb
+++ b/test/rubygems/test_require.rb
@@ -230,7 +230,7 @@ class TestGemRequire < Gem::TestCase
 
     pend "not installed yet" unless RbConfig::TOPDIR
 
-    lib_dir = File.expand_path("../../lib", File.dirname(__FILE__))
+    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/