diff --git a/lib/rubygems/specification_policy.rb b/lib/rubygems/specification_policy.rb
index 6655825287..77d5863819 100644
--- a/lib/rubygems/specification_policy.rb
+++ b/lib/rubygems/specification_policy.rb
@@ -7,7 +7,7 @@ class Gem::SpecificationPolicy
 
   VALID_NAME_PATTERN = /\A[a-zA-Z0-9\.\-\_]+\z/ # :nodoc:
 
-  SPECIAL_CHARACTERS = /\A[#{Regexp.escape('.-_')}]+/ # :nodoc:
+  SPECIAL_CHARACTERS = /\A[#{Regexp.escape(".-_")}]+/ # :nodoc:
 
   VALID_URI_PATTERN = %r{\Ahttps?:\/\/([^\s:@]+:[^\s:@]*@)?[A-Za-z\d\-]+(\.[A-Za-z\d\-]+)+\.?(:\d{1,5})?([\/?]\S*)?\z} # :nodoc:
 
diff --git a/test/rubygems/test_gem_commands_environment_command.rb b/test/rubygems/test_gem_commands_environment_command.rb
index f527574c07..48252d84d4 100644
--- a/test/rubygems/test_gem_commands_environment_command.rb
+++ b/test/rubygems/test_gem_commands_environment_command.rb
@@ -30,7 +30,7 @@ class TestGemCommandsEnvironmentCommand < Gem::TestCase
     assert_match(/USER INSTALLATION DIRECTORY: #{Regexp.escape Gem.user_dir}/,
                  @ui.output)
     assert_match(/RUBYGEMS PREFIX: /, @ui.output)
-    assert_match(/RUBY EXECUTABLE:.*#{RbConfig::CONFIG['ruby_install_name']}/,
+    assert_match(/RUBY EXECUTABLE:.*#{RbConfig::CONFIG["ruby_install_name"]}/,
                  @ui.output)
     assert_match(/GIT EXECUTABLE: #{@cmd.send(:git_path)}/, @ui.output)
     assert_match(/SYSTEM CONFIGURATION DIRECTORY:/, @ui.output)
diff --git a/test/rubygems/test_gem_dependency_installer.rb b/test/rubygems/test_gem_dependency_installer.rb
index ac84a589e5..9eb6049df1 100644
--- a/test/rubygems/test_gem_dependency_installer.rb
+++ b/test/rubygems/test_gem_dependency_installer.rb
@@ -621,7 +621,7 @@ class TestGemDependencyInstaller < Gem::TestCase
 
     env = "/\\S+/env" unless Gem.win_platform?
 
-    assert_match(/\A#!#{env} #{RbConfig::CONFIG['ruby_install_name']}\n/,
+    assert_match(/\A#!#{env} #{RbConfig::CONFIG["ruby_install_name"]}\n/,
                  File.read(File.join(@gemhome, "bin", "a_bin")))
   end
 
diff --git a/test/rubygems/test_gem_ext_builder.rb b/test/rubygems/test_gem_ext_builder.rb
index b1b6356020..493aaa1b53 100644
--- a/test/rubygems/test_gem_ext_builder.rb
+++ b/test/rubygems/test_gem_ext_builder.rb
@@ -48,9 +48,9 @@ install:
 
     results = results.join("\n").b
 
-    assert_match(/DESTDIR\\=#{ENV['DESTDIR']} clean$/,   results)
-    assert_match(/DESTDIR\\=#{ENV['DESTDIR']}$/,         results)
-    assert_match(/DESTDIR\\=#{ENV['DESTDIR']} install$/, results)
+    assert_match(/DESTDIR\\=#{ENV["DESTDIR"]} clean$/,   results)
+    assert_match(/DESTDIR\\=#{ENV["DESTDIR"]}$/,         results)
+    assert_match(/DESTDIR\\=#{ENV["DESTDIR"]} install$/, results)
 
     unless results.include?("nmake")
       assert_match(/^clean: destination$/,   results)
@@ -77,9 +77,9 @@ install:
 
     results = results.join("\n").b
 
-    assert_match(/DESTDIR\\=#{ENV['DESTDIR']} clean$/,   results)
-    assert_match(/DESTDIR\\=#{ENV['DESTDIR']}$/,         results)
-    assert_match(/DESTDIR\\=#{ENV['DESTDIR']} install$/, results)
+    assert_match(/DESTDIR\\=#{ENV["DESTDIR"]} clean$/,   results)
+    assert_match(/DESTDIR\\=#{ENV["DESTDIR"]}$/,         results)
+    assert_match(/DESTDIR\\=#{ENV["DESTDIR"]} install$/, results)
   end
 
   def test_custom_make_with_options