diff --git a/lib/rubygems/installer.rb b/lib/rubygems/installer.rb
index afb20634ee..96e777aaee 100644
--- a/lib/rubygems/installer.rb
+++ b/lib/rubygems/installer.rb
@@ -810,7 +810,7 @@ TEXT
     ruby_exe = "#{rb_config["RUBY_INSTALL_NAME"]}#{rb_config["EXEEXT"]}"
     ruby_exe = "ruby.exe" if ruby_exe.empty?
 
-    if File.exist?(File.join bindir, ruby_exe)
+    if File.exist?(File.join(bindir, ruby_exe))
       # stub & ruby.exe within same folder.  Portable
       <<-TEXT
 @ECHO OFF
diff --git a/lib/rubygems/request_set/gem_dependency_api.rb b/lib/rubygems/request_set/gem_dependency_api.rb
index 11b35dd8cd..8d74d832de 100644
--- a/lib/rubygems/request_set/gem_dependency_api.rb
+++ b/lib/rubygems/request_set/gem_dependency_api.rb
@@ -532,8 +532,8 @@ Gem dependencies file #{@path} includes git reference for both ref/branch and ta
   # platform matches the current platform.
 
   def gem_platforms(name, options) # :nodoc:
-    platform_names = Array(options.delete :platform)
-    platform_names.concat Array(options.delete :platforms)
+    platform_names = Array(options.delete(:platform))
+    platform_names.concat Array(options.delete(:platforms))
     platform_names.concat @current_platforms if @current_platforms
 
     return true if platform_names.empty?
diff --git a/test/rubygems/bundler_test_gem.rb b/test/rubygems/bundler_test_gem.rb
index ed2ca44141..1e083ef93f 100644
--- a/test/rubygems/bundler_test_gem.rb
+++ b/test/rubygems/bundler_test_gem.rb
@@ -36,7 +36,7 @@ class TestBundlerGem < Gem::TestCase
           s.files << discover_path
         end
 
-        write_file(File.join "gems", spec.full_name, discover_path) do |fp|
+        write_file(File.join("gems", spec.full_name, discover_path)) do |fp|
           fp.puts "# #{spec.full_name}"
         end
 
@@ -44,11 +44,11 @@ class TestBundlerGem < Gem::TestCase
       end
       Gem.refresh
 
-      write_file(File.join Dir.pwd, "Gemfile") do |fp|
+      write_file(File.join(Dir.pwd, "Gemfile")) do |fp|
         fp.puts "source 'https://rubygems.org'"
         fp.puts "gem '#{foo1.name}', '#{foo1.version}'"
       end
-      Gem.use_gemdeps(File.join Dir.pwd, "Gemfile")
+      Gem.use_gemdeps(File.join(Dir.pwd, "Gemfile"))
 
       expected = [
         File.expand_path("test/rubygems/sff/discover.rb", PROJECT_DIR),
diff --git a/test/rubygems/test_deprecate.rb b/test/rubygems/test_deprecate.rb
index 2a568b21e9..0b5afa3782 100644
--- a/test/rubygems/test_deprecate.rb
+++ b/test/rubygems/test_deprecate.rb
@@ -28,7 +28,7 @@ class TestDeprecate < Gem::TestCase
     assert_equal true, Gem::Deprecate.skip
 
     Gem::Deprecate.skip = nil
-    assert([true,false].include? Gem::Deprecate.skip)
+    assert([true,false].include?(Gem::Deprecate.skip))
   end
 
   def test_skip
diff --git a/test/rubygems/test_gem.rb b/test/rubygems/test_gem.rb
index c2d123f695..f3b62d36c7 100644
--- a/test/rubygems/test_gem.rb
+++ b/test/rubygems/test_gem.rb
@@ -734,7 +734,7 @@ class TestGem < Gem::TestCase
         s.files << discover_path
       end
 
-      write_file(File.join "gems", spec.full_name, discover_path) do |fp|
+      write_file(File.join("gems", spec.full_name, discover_path)) do |fp|
         fp.puts "# #{spec.full_name}"
       end
 
@@ -766,7 +766,7 @@ class TestGem < Gem::TestCase
         s.files << discover_path
       end
 
-      write_file(File.join "gems", spec.full_name, discover_path) do |fp|
+      write_file(File.join("gems", spec.full_name, discover_path)) do |fp|
         fp.puts "# #{spec.full_name}"
       end
 
diff --git a/test/rubygems/test_gem_commands_unpack_command.rb b/test/rubygems/test_gem_commands_unpack_command.rb
index 1d9d0b6bd0..7c13b64956 100644
--- a/test/rubygems/test_gem_commands_unpack_command.rb
+++ b/test/rubygems/test_gem_commands_unpack_command.rb
@@ -15,7 +15,7 @@ class TestGemCommandsUnpackCommand < Gem::TestCase
     util_make_gems
 
     assert_equal(
-      @cmd.find_in_cache(File.basename @a1.cache_file),
+      @cmd.find_in_cache(File.basename(@a1.cache_file)),
       @a1.cache_file,
       "found a-1.gem in the cache"
     )
diff --git a/test/rubygems/test_gem_request.rb b/test/rubygems/test_gem_request.rb
index ebdc98eef5..a3fd11c27e 100644
--- a/test/rubygems/test_gem_request.rb
+++ b/test/rubygems/test_gem_request.rb
@@ -185,7 +185,7 @@ class TestGemRequest < Gem::TestCase
   end
 
   def test_fetch
-    uri = Gem::Uri.new(URI.parse "#{@gem_repo}/specs.#{Gem.marshal_version}")
+    uri = Gem::Uri.new(URI.parse("#{@gem_repo}/specs.#{Gem.marshal_version}"))
     response = util_stub_net_http(:body => :junk, :code => 200) do
       @request = make_request(uri, Net::HTTP::Get, nil, nil)
 
@@ -198,7 +198,7 @@ class TestGemRequest < Gem::TestCase
 
   def test_fetch_basic_auth
     Gem.configuration.verbose = :really
-    uri = Gem::Uri.new(URI.parse "https://user:pass@example.rubygems/specs.#{Gem.marshal_version}")
+    uri = Gem::Uri.new(URI.parse("https://user:pass@example.rubygems/specs.#{Gem.marshal_version}"))
     conn = util_stub_net_http(:body => :junk, :code => 200) do |c|
       use_ui @ui do
         @request = make_request(uri, Net::HTTP::Get, nil, nil)
@@ -214,7 +214,7 @@ class TestGemRequest < Gem::TestCase
 
   def test_fetch_basic_auth_encoded
     Gem.configuration.verbose = :really
-    uri = Gem::Uri.new(URI.parse "https://user:%7BDEScede%7Dpass@example.rubygems/specs.#{Gem.marshal_version}")
+    uri = Gem::Uri.new(URI.parse("https://user:%7BDEScede%7Dpass@example.rubygems/specs.#{Gem.marshal_version}"))
 
     conn = util_stub_net_http(:body => :junk, :code => 200) do |c|
       use_ui @ui do
@@ -231,7 +231,7 @@ class TestGemRequest < Gem::TestCase
 
   def test_fetch_basic_oauth_encoded
     Gem.configuration.verbose = :really
-    uri = Gem::Uri.new(URI.parse "https://%7BDEScede%7Dpass:x-oauth-basic@example.rubygems/specs.#{Gem.marshal_version}")
+    uri = Gem::Uri.new(URI.parse("https://%7BDEScede%7Dpass:x-oauth-basic@example.rubygems/specs.#{Gem.marshal_version}"))
 
     conn = util_stub_net_http(:body => :junk, :code => 200) do |c|
       use_ui @ui do
@@ -247,7 +247,7 @@ class TestGemRequest < Gem::TestCase
   end
 
   def test_fetch_head
-    uri = Gem::Uri.new(URI.parse "#{@gem_repo}/specs.#{Gem.marshal_version}")
+    uri = Gem::Uri.new(URI.parse("#{@gem_repo}/specs.#{Gem.marshal_version}"))
     response = util_stub_net_http(:body => "", :code => 200) do |_conn|
       @request = make_request(uri, Net::HTTP::Get, nil, nil)
       @request.fetch
@@ -258,7 +258,7 @@ class TestGemRequest < Gem::TestCase
   end
 
   def test_fetch_unmodified
-    uri = Gem::Uri.new(URI.parse "#{@gem_repo}/specs.#{Gem.marshal_version}")
+    uri = Gem::Uri.new(URI.parse("#{@gem_repo}/specs.#{Gem.marshal_version}"))
     t = Time.utc(2013, 1, 2, 3, 4, 5)
     conn, response = util_stub_net_http(:body => "", :code => 304) do |c|
       @request = make_request(uri, Net::HTTP::Get, t, nil)
diff --git a/test/rubygems/test_require.rb b/test/rubygems/test_require.rb
index 0afe3a61d6..543a382cc4 100644
--- a/test/rubygems/test_require.rb
+++ b/test/rubygems/test_require.rb
@@ -383,8 +383,8 @@ class TestGemRequire < Gem::TestCase
 
     # 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")
+    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"