12 files changed, 69 insertions, 22 deletions
diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
index 83ba0a8497..65dd28b3d7 100644
--- a/actionpack/test/abstract_unit.rb
+++ b/actionpack/test/abstract_unit.rb
@@ -431,14 +431,16 @@ end
 class ActiveSupport::TestCase
   include ActiveSupport::Testing::MethodCallAssertions
 
-  # Skips the current run on Rubinius using Minitest::Assertions#skip
-  private def rubinius_skip(message = "")
-    skip message if RUBY_ENGINE == "rbx"
-  end
-  # Skips the current run on JRuby using Minitest::Assertions#skip
-  private def jruby_skip(message = "")
-    skip message if defined?(JRUBY_VERSION)
-  end
+  private
+    # Skips the current run on Rubinius using Minitest::Assertions#skip
+    def rubinius_skip(message = "")
+      skip message if RUBY_ENGINE == "rbx"
+    end
+
+    # Skips the current run on JRuby using Minitest::Assertions#skip
+    def jruby_skip(message = "")
+      skip message if defined?(JRUBY_VERSION)
+    end
 end
 
 class DrivenByRackTest < ActionDispatch::SystemTestCase
diff --git a/actionpack/test/controller/http_token_authentication_test.rb b/actionpack/test/controller/http_token_authentication_test.rb
index 672aa1351c..103123f98c 100644
--- a/actionpack/test/controller/http_token_authentication_test.rb
+++ b/actionpack/test/controller/http_token_authentication_test.rb
@@ -150,7 +150,7 @@ class HttpTokenAuthenticationTest < ActionController::TestCase
   end
 
   test "token_and_options returns empty string with empty token" do
-    token = "".dup
+    token = +""
     actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
     expected = token
     assert_equal(expected, actual)
diff --git a/actionpack/test/controller/new_base/bare_metal_test.rb b/actionpack/test/controller/new_base/bare_metal_test.rb
index b049022a06..7572d514fb 100644
--- a/actionpack/test/controller/new_base/bare_metal_test.rb
+++ b/actionpack/test/controller/new_base/bare_metal_test.rb
@@ -13,7 +13,7 @@ module BareMetalTest
     test "response body is a Rack-compatible response" do
       status, headers, body = BareController.action(:index).call(Rack::MockRequest.env_for("/"))
       assert_equal 200, status
-      string = "".dup
+      string = +""
 
       body.each do |part|
         assert part.is_a?(String), "Each part of the body must be a String"
diff --git a/actionpack/test/controller/new_base/render_context_test.rb b/actionpack/test/controller/new_base/render_context_test.rb
index 07fbadae9f..5e570a1d79 100644
--- a/actionpack/test/controller/new_base/render_context_test.rb
+++ b/actionpack/test/controller/new_base/render_context_test.rb
@@ -32,10 +32,11 @@ module RenderContext
       "controller context!"
     end
 
-    # 3) Set view_context to self
-    private def view_context
-      self
-    end
+    private
+      # 3) Set view_context to self
+      def view_context
+        self
+      end
   end
 
   class RenderContextTest < Rack::TestCase
diff --git a/actionpack/test/controller/redirect_test.rb b/actionpack/test/controller/redirect_test.rb
index 461e627154..998498e1b2 100644
--- a/actionpack/test/controller/redirect_test.rb
+++ b/actionpack/test/controller/redirect_test.rb
@@ -214,6 +214,13 @@ class RedirectTest < ActionController::TestCase
     assert_equal "http://test.host/things/stuff", redirect_to_url
   end
 
+  def test_relative_url_redirect_host_with_port
+    request.host = "test.host:1234"
+    get :relative_url_redirect_with_status
+    assert_response 302
+    assert_equal "http://test.host:1234/things/stuff", redirect_to_url
+  end
+
   def test_simple_redirect_using_options
     get :host_redirect
     assert_response :redirect
diff --git a/actionpack/test/controller/routing_test.rb b/actionpack/test/controller/routing_test.rb
index a7033b2d30..a2a811f090 100644
--- a/actionpack/test/controller/routing_test.rb
+++ b/actionpack/test/controller/routing_test.rb
@@ -674,7 +674,7 @@ class LegacyRouteSetTests < ActiveSupport::TestCase
     assert_equal "/page/foo", url_for(rs, controller: "content", action: "show_page", id: "foo")
     assert_equal({ controller: "content", action: "show_page", id: "foo" }, rs.recognize_path("/page/foo"))
 
-    token = "\321\202\320\265\320\272\321\201\321\202".dup # 'text' in Russian
+    token = +"\321\202\320\265\320\272\321\201\321\202" # 'text' in Russian
     token.force_encoding(Encoding::BINARY)
     escaped_token = CGI.escape(token)
 
diff --git a/actionpack/test/controller/send_file_test.rb b/actionpack/test/controller/send_file_test.rb
index 7b1a52b277..c917cdf761 100644
--- a/actionpack/test/controller/send_file_test.rb
+++ b/actionpack/test/controller/send_file_test.rb
@@ -144,7 +144,7 @@ class SendFileTest < ActionController::TestCase
       get :test_send_file_headers_bang
 
       assert_equal "image/png", response.content_type
-      assert_equal 'disposition; filename="filename"', response.get_header("Content-Disposition")
+      assert_equal %(disposition; filename="filename"; filename*=UTF-8''filename), response.get_header("Content-Disposition")
       assert_equal "binary", response.get_header("Content-Transfer-Encoding")
       assert_equal "private", response.get_header("Cache-Control")
     end
@@ -153,7 +153,7 @@ class SendFileTest < ActionController::TestCase
   def test_send_file_headers_with_disposition_as_a_symbol
     get :test_send_file_headers_with_disposition_as_a_symbol
 
-    assert_equal 'disposition; filename="filename"', response.get_header("Content-Disposition")
+    assert_equal %(disposition; filename="filename"; filename*=UTF-8''filename), response.get_header("Content-Disposition")
   end
 
   def test_send_file_headers_with_mime_lookup_with_symbol
diff --git a/actionpack/test/dispatch/content_disposition_test.rb b/actionpack/test/dispatch/content_disposition_test.rb
new file mode 100644
index 0000000000..3f5959da6e
--- /dev/null
+++ b/actionpack/test/dispatch/content_disposition_test.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+module ActionDispatch
+  class ContentDispositionTest < ActiveSupport::TestCase
+    test "encoding a Latin filename" do
+      disposition = Http::ContentDisposition.new(disposition: :inline, filename: "racecar.jpg")
+
+      assert_equal %(filename="racecar.jpg"), disposition.ascii_filename
+      assert_equal "filename*=UTF-8''racecar.jpg", disposition.utf8_filename
+      assert_equal "inline; #{disposition.ascii_filename}; #{disposition.utf8_filename}", disposition.to_s
+    end
+
+    test "encoding a Latin filename with accented characters" do
+      disposition = Http::ContentDisposition.new(disposition: :inline, filename: "råcëçâr.jpg")
+
+      assert_equal %(filename="racecar.jpg"), disposition.ascii_filename
+      assert_equal "filename*=UTF-8''r%C3%A5c%C3%AB%C3%A7%C3%A2r.jpg", disposition.utf8_filename
+      assert_equal "inline; #{disposition.ascii_filename}; #{disposition.utf8_filename}", disposition.to_s
+    end
+
+    test "encoding a non-Latin filename" do
+      disposition = Http::ContentDisposition.new(disposition: :inline, filename: "автомобиль.jpg")
+
+      assert_equal %(filename="%3F%3F%3F%3F%3F%3F%3F%3F%3F%3F.jpg"), disposition.ascii_filename
+      assert_equal "filename*=UTF-8''%D0%B0%D0%B2%D1%82%D0%BE%D0%BC%D0%BE%D0%B1%D0%B8%D0%BB%D1%8C.jpg", disposition.utf8_filename
+      assert_equal "inline; #{disposition.ascii_filename}; #{disposition.utf8_filename}", disposition.to_s
+    end
+
+    test "without filename" do
+      disposition = Http::ContentDisposition.new(disposition: :inline, filename: nil)
+
+      assert_equal "inline", disposition.to_s
+    end
+  end
+end
diff --git a/actionpack/test/dispatch/debug_exceptions_test.rb b/actionpack/test/dispatch/debug_exceptions_test.rb
index 44b79c0e5d..37399cfd07 100644
--- a/actionpack/test/dispatch/debug_exceptions_test.rb
+++ b/actionpack/test/dispatch/debug_exceptions_test.rb
@@ -368,7 +368,7 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
     })
     assert_response 500
 
-    assert_includes(body, CGI.escapeHTML(PP.pp(params, "".dup, 200)))
+    assert_includes(body, CGI.escapeHTML(PP.pp(params, +"", 200)))
   end
 
   test "sets the HTTP charset parameter" do
diff --git a/actionpack/test/dispatch/prefix_generation_test.rb b/actionpack/test/dispatch/prefix_generation_test.rb
index 85ea04356a..7a7a201b11 100644
--- a/actionpack/test/dispatch/prefix_generation_test.rb
+++ b/actionpack/test/dispatch/prefix_generation_test.rb
@@ -13,7 +13,7 @@ module TestGenerationPrefix
     end
 
     def self.model_name
-      klass = "Post".dup
+      klass = +"Post"
       def klass.name; self end
 
       ActiveModel::Name.new(klass)
diff --git a/actionpack/test/dispatch/static_test.rb b/actionpack/test/dispatch/static_test.rb
index 6b69cd9999..d44aa00122 100644
--- a/actionpack/test/dispatch/static_test.rb
+++ b/actionpack/test/dispatch/static_test.rb
@@ -31,7 +31,7 @@ module StaticTests
   end
 
   def test_handles_urls_with_ascii_8bit
-    assert_equal "Hello, World!", get("/doorkeeper%E3E4".dup.force_encoding("ASCII-8BIT")).body
+    assert_equal "Hello, World!", get((+"/doorkeeper%E3E4").force_encoding("ASCII-8BIT")).body
   end
 
   def test_handles_urls_with_ascii_8bit_on_win_31j
@@ -39,7 +39,7 @@ module StaticTests
       Encoding.default_internal = "Windows-31J"
       Encoding.default_external = "Windows-31J"
     end
-    assert_equal "Hello, World!", get("/doorkeeper%E3E4".dup.force_encoding("ASCII-8BIT")).body
+    assert_equal "Hello, World!", get((+"/doorkeeper%E3E4").force_encoding("ASCII-8BIT")).body
   end
 
   def test_handles_urls_with_null_byte
diff --git a/actionpack/test/journey/router/utils_test.rb b/actionpack/test/journey/router/utils_test.rb
index 2d09098f11..472f1bf35e 100644
--- a/actionpack/test/journey/router/utils_test.rb
+++ b/actionpack/test/journey/router/utils_test.rb
@@ -23,7 +23,7 @@ module ActionDispatch
         end
 
         def test_uri_unescape_with_utf8_string
-          assert_equal "Šašinková", Utils.unescape_uri("%C5%A0a%C5%A1inkov%C3%A1".dup.force_encoding(Encoding::US_ASCII))
+          assert_equal "Šašinková", Utils.unescape_uri((+"%C5%A0a%C5%A1inkov%C3%A1").force_encoding(Encoding::US_ASCII))
         end
 
         def test_normalize_path_not_greedy