Merge branch 'master' into fix_26964

33 files changed, 133 insertions, 116 deletions

diff --git a/actionpack/test/controller/filters_test.rb b/actionpack/test/controller/filters_test.rb
index e0fa1fbab8..f9701585a9 100644
--- a/actionpack/test/controller/filters_test.rb
+++ b/actionpack/test/controller/filters_test.rb
@@ -55,7 +55,7 @@ class FilterTest < ActionController::TestCase
       end
     end
 
-    protected
+    private
       (1..3).each do |i|
         define_method "try_#{i}" do
           instance_variable_set :@try, i
@@ -296,7 +296,7 @@ class FilterTest < ActionController::TestCase
       render inline: "ran action"
     end
 
-    protected
+    private
       def find_user
         @ran_filter ||= []
         @ran_filter << "find_user"
@@ -428,7 +428,7 @@ class FilterTest < ActionController::TestCase
       render plain: "bar"
     end
 
-    protected
+    private
       def first
         @first = true
       end
@@ -1040,7 +1040,7 @@ class YieldingAroundFiltersTest < ActionController::TestCase
     assert_equal 3, controller.instance_variable_get(:@try)
   end
 
-  protected
+  private
     def test_process(controller, action = "show")
       @controller = controller.is_a?(Class) ? controller.new : controller
       process(action)
diff --git a/actionpack/test/controller/flash_hash_test.rb b/actionpack/test/controller/flash_hash_test.rb
index 6b3abdd5be..45b598a594 100644
--- a/actionpack/test/controller/flash_hash_test.rb
+++ b/actionpack/test/controller/flash_hash_test.rb
@@ -63,10 +63,10 @@ module ActionDispatch
       assert_equal({ "flashes" => { "foo" => "bar" }, "discard" => [] }, @hash.to_session_value)
 
       @hash.discard("foo")
-      assert_equal(nil, @hash.to_session_value)
+      assert_nil(@hash.to_session_value)
 
       @hash.sweep
-      assert_equal(nil, @hash.to_session_value)
+      assert_nil(@hash.to_session_value)
     end
 
     def test_from_session_value
@@ -75,7 +75,7 @@ module ActionDispatch
       session = Marshal.load(Base64.decode64(rails_3_2_cookie))
       hash = Flash::FlashHash.from_session_value(session["flash"])
       assert_equal({ "greeting" => "Hello" }, hash.to_hash)
-      assert_equal(nil, hash.to_session_value)
+      assert_nil(hash.to_session_value)
     end
 
     def test_from_session_value_on_json_serializer
@@ -84,7 +84,7 @@ module ActionDispatch
       hash = Flash::FlashHash.from_session_value(session["flash"])
 
       assert_equal({ "greeting" => "Hello" }, hash.to_hash)
-      assert_equal(nil, hash.to_session_value)
+      assert_nil(hash.to_session_value)
       assert_equal "Hello", hash[:greeting]
       assert_equal "Hello", hash["greeting"]
     end
diff --git a/actionpack/test/controller/http_token_authentication_test.rb b/actionpack/test/controller/http_token_authentication_test.rb
index 3842136682..09d2793c9a 100644
--- a/actionpack/test/controller/http_token_authentication_test.rb
+++ b/actionpack/test/controller/http_token_authentication_test.rb
@@ -166,8 +166,7 @@ class HttpTokenAuthenticationTest < ActionController::TestCase
 
   test "token_and_options returns nil with no value after the equal sign" do
     actual = ActionController::HttpAuthentication::Token.token_and_options(malformed_request).first
-    expected = nil
-    assert_equal(expected, actual)
+    assert_nil actual
   end
 
   test "raw_params returns a tuple of two key value pair strings" do
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
index d3aa81a0f7..4fae4071b1 100644
--- a/actionpack/test/controller/integration_test.rb
+++ b/actionpack/test/controller/integration_test.rb
@@ -289,7 +289,7 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
       assert_response :success
       assert_equal "bar", body
 
-      assert_equal nil, headers["Set-Cookie"]
+      assert_nil headers["Set-Cookie"]
       assert_equal({ "foo" => "bar" }, cookies.to_hash)
     end
   end
@@ -308,7 +308,7 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
       assert_response :success
       assert_equal "bar", body
 
-      assert_equal nil, headers["Set-Cookie"]
+      assert_nil headers["Set-Cookie"]
       assert_equal({ "foo" => "bar" }, cookies.to_hash)
     end
   end
diff --git a/actionpack/test/controller/mime/accept_format_test.rb b/actionpack/test/controller/mime/accept_format_test.rb
index a2834c9f39..a22fa39051 100644
--- a/actionpack/test/controller/mime/accept_format_test.rb
+++ b/actionpack/test/controller/mime/accept_format_test.rb
@@ -40,7 +40,7 @@ class PostController < AbstractPostController
     respond_to(:html, :iphone, :js)
   end
 
-protected
+private
 
   def with_iphone
     request.format = "iphone" if request.env["HTTP_ACCEPT"] == "text/iphone"
diff --git a/actionpack/test/controller/mime/respond_to_test.rb b/actionpack/test/controller/mime/respond_to_test.rb
index c5f8165d04..818dc119eb 100644
--- a/actionpack/test/controller/mime/respond_to_test.rb
+++ b/actionpack/test/controller/mime/respond_to_test.rb
@@ -273,7 +273,7 @@ class RespondToController < ActionController::Base
     end
   end
 
-  protected
+  private
     def set_layout
       case action_name
       when "all_types_with_layout", "iphone_with_html_response_type"
diff --git a/actionpack/test/controller/new_base/bare_metal_test.rb b/actionpack/test/controller/new_base/bare_metal_test.rb
index 9956f0b107..054757fab3 100644
--- a/actionpack/test/controller/new_base/bare_metal_test.rb
+++ b/actionpack/test/controller/new_base/bare_metal_test.rb
@@ -52,7 +52,7 @@ module BareMetalTest
       controller.set_request!(ActionDispatch::Request.empty)
       controller.set_response!(BareController.make_response!(controller.request))
       controller.index
-      assert_equal nil, controller.response_body
+      assert_nil controller.response_body
     end
   end
 
diff --git a/actionpack/test/controller/new_base/base_test.rb b/actionpack/test/controller/new_base/base_test.rb
index 3765d406fc..b891df4c0f 100644
--- a/actionpack/test/controller/new_base/base_test.rb
+++ b/actionpack/test/controller/new_base/base_test.rb
@@ -25,7 +25,7 @@ module Dispatching
       render body: "actions: #{action_methods.to_a.sort.join(', ')}"
     end
 
-    protected
+    private
       def authenticate
       end
   end
diff --git a/actionpack/test/controller/new_base/render_context_test.rb b/actionpack/test/controller/new_base/render_context_test.rb
index b64468a94e..25b73ac78c 100644
--- a/actionpack/test/controller/new_base/render_context_test.rb
+++ b/actionpack/test/controller/new_base/render_context_test.rb
@@ -26,16 +26,14 @@ module RenderContext
       render action: "hello_world", layout: "basic"
     end
 
-    protected
-
-      # 3) Set view_context to self
-      def view_context
-        self
-      end
+    protected def __controller_method__
+      "controller context!"
+    end
 
-      def __controller_method__
-        "controller context!"
-      end
+    # 3) Set view_context to self
+    private def view_context
+      self
+    end
   end
 
   class RenderContextTest < Rack::TestCase
diff --git a/actionpack/test/controller/new_base/render_streaming_test.rb b/actionpack/test/controller/new_base/render_streaming_test.rb
index 64b799f826..1177b8b03e 100644
--- a/actionpack/test/controller/new_base/render_streaming_test.rb
+++ b/actionpack/test/controller/new_base/render_streaming_test.rb
@@ -101,12 +101,12 @@ module RenderStreaming
       assert_body "Hello world, I'm here!"
       assert_status 200
       assert_equal "22", headers["Content-Length"]
-      assert_equal nil, headers["Transfer-Encoding"]
+      assert_nil headers["Transfer-Encoding"]
     end
 
     def assert_streaming!(cache = "no-cache")
       assert_status 200
-      assert_equal nil, headers["Content-Length"]
+      assert_nil headers["Content-Length"]
       assert_equal "chunked", headers["Transfer-Encoding"]
       assert_equal cache, headers["Cache-Control"]
     end
diff --git a/actionpack/test/controller/parameter_encoding_test.rb b/actionpack/test/controller/parameter_encoding_test.rb
index 7840b4f5c4..234d0bddd1 100644
--- a/actionpack/test/controller/parameter_encoding_test.rb
+++ b/actionpack/test/controller/parameter_encoding_test.rb
@@ -1,9 +1,8 @@
 require "abstract_unit"
 
 class ParameterEncodingController < ActionController::Base
-  parameter_encoding :test_bar,          :bar, Encoding::ASCII_8BIT
-  parameter_encoding :test_baz,          :baz, Encoding::ISO_8859_1
-  parameter_encoding :test_baz_to_ascii, :baz, Encoding::ASCII_8BIT
+  skip_parameter_encoding :test_bar
+  skip_parameter_encoding :test_all_values_encoding
 
   def test_foo
     render body: params[:foo].encoding
@@ -13,16 +12,8 @@ class ParameterEncodingController < ActionController::Base
     render body: params[:bar].encoding
   end
 
-  def test_baz
-    render body: params[:baz].encoding
-  end
-
-  def test_no_change_to_baz
-    render body: params[:baz].encoding
-  end
-
-  def test_baz_to_ascii
-    render body: params[:baz].encoding
+  def test_all_values_encoding
+    render body: ::JSON.dump(params.values.map(&:encoding).map(&:name))
   end
 end
 
@@ -36,32 +27,18 @@ class ParameterEncodingTest < ActionController::TestCase
     assert_equal "UTF-8", @response.body
   end
 
-  test "properly transcodes ASCII_8BIT parameters into declared encodings" do
+  test "properly encodes ASCII_8BIT parameters into binary" do
     post :test_bar, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
 
     assert_response :success
     assert_equal "ASCII-8BIT", @response.body
   end
 
-  test "properly transcodes ISO_8859_1 parameters into declared encodings" do
-    post :test_baz, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
-
-    assert_response :success
-    assert_equal "ISO-8859-1", @response.body
-  end
-
-  test "does not transcode parameters when not specified" do
-    post :test_no_change_to_baz, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+  test "properly encodes all ASCII_8BIT parameters into binary" do
+    post :test_all_values_encoding, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
 
     assert_response :success
-    assert_equal "UTF-8", @response.body
-  end
-
-  test "respects different encoding declarations for a param per action" do
-    post :test_baz_to_ascii, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
-
-    assert_response :success
-    assert_equal "ASCII-8BIT", @response.body
+    assert_equal ["ASCII-8BIT"], JSON.parse(@response.body).uniq
   end
 
   test "does not raise an error when passed a param declared as ASCII-8BIT that contains invalid bytes" do
diff --git a/actionpack/test/controller/parameters/parameters_permit_test.rb b/actionpack/test/controller/parameters/parameters_permit_test.rb
index 92e134d313..b62a3d6d7b 100644
--- a/actionpack/test/controller/parameters/parameters_permit_test.rb
+++ b/actionpack/test/controller/parameters/parameters_permit_test.rb
@@ -141,7 +141,7 @@ class ParametersPermitTest < ActiveSupport::TestCase
     permitted = params.permit(:a, c: [], b: [])
     assert_equal 1, permitted[:a]
     assert_equal [1, 2, 3], permitted[:b]
-    assert_equal nil, permitted[:c]
+    assert_nil permitted[:c]
   end
 
   test "key to empty array: arrays of permitted scalars pass" do
@@ -216,7 +216,7 @@ class ParametersPermitTest < ActiveSupport::TestCase
   test "fetch with a default value of a hash does not mutate the object" do
     params = ActionController::Parameters.new({})
     params.fetch :foo, {}
-    assert_equal nil, params[:foo]
+    assert_nil params[:foo]
   end
 
   test "hashes in array values get wrapped" do
@@ -254,8 +254,8 @@ class ParametersPermitTest < ActiveSupport::TestCase
   end
 
   test "fetch doesnt raise ParameterMissing exception if there is a default that is nil" do
-    assert_equal nil, @params.fetch(:foo, nil)
-    assert_equal nil, @params.fetch(:foo) { nil }
+    assert_nil @params.fetch(:foo, nil)
+    assert_nil @params.fetch(:foo) { nil }
   end
 
   test "KeyError in fetch block should not be covered up" do
diff --git a/actionpack/test/controller/params_wrapper_test.rb b/actionpack/test/controller/params_wrapper_test.rb
index 46a2ab8ccf..faa57c4559 100644
--- a/actionpack/test/controller/params_wrapper_test.rb
+++ b/actionpack/test/controller/params_wrapper_test.rb
@@ -50,7 +50,7 @@ class ParamsWrapperTest < ActionController::TestCase
     with_default_wrapper_options do
       @request.env["CONTENT_TYPE"] = "application/json"
       post :parse, params: { "username" => "sikachu" }
-      assert_equal @request.filtered_parameters, "controller" => "params_wrapper_test/users", "action" => "parse", "username" => "sikachu", "user" => { "username" => "sikachu" }
+      assert_equal({ "controller" => "params_wrapper_test/users", "action" => "parse", "username" => "sikachu", "user" => { "username" => "sikachu" } }, @request.filtered_parameters)
     end
   end
 
diff --git a/actionpack/test/controller/redirect_test.rb b/actionpack/test/controller/redirect_test.rb
index 0e61b92bcf..e4e968dfdb 100644
--- a/actionpack/test/controller/redirect_test.rb
+++ b/actionpack/test/controller/redirect_test.rb
@@ -123,7 +123,7 @@ class RedirectController < ActionController::Base
 
   def rescue_errors(e) raise e end
 
-  protected
+  private
     def dashbord_url(id, message)
       url_for action: "dashboard", params: { "id" => id, "message" => message }
     end
diff --git a/actionpack/test/controller/request/test_request_test.rb b/actionpack/test/controller/request/test_request_test.rb
index da6fa1388b..b67ae72c0a 100644
--- a/actionpack/test/controller/request/test_request_test.rb
+++ b/actionpack/test/controller/request/test_request_test.rb
@@ -8,7 +8,7 @@ class ActionController::TestRequestTest < ActionController::TestCase
 
   def test_mutating_session_options_does_not_affect_default_options
     @request.session_options[:myparam] = 123
-    assert_equal nil, ActionController::TestSession::DEFAULT_OPTIONS[:myparam]
+    assert_nil ActionController::TestSession::DEFAULT_OPTIONS[:myparam]
   end
 
   def test_content_length_has_bytes_count_value
@@ -17,8 +17,8 @@ class ActionController::TestRequestTest < ActionController::TestCase
     @request.set_header "CONTENT_TYPE", "application/json"
     @request.assign_parameters(@routes, "test", "create", non_ascii_parameters,
                                "/test", [:data, :controller, :action])
-    assert_equal(@request.get_header("CONTENT_LENGTH"),
-                 StringIO.new(non_ascii_parameters.to_json).length.to_s)
+    assert_equal(StringIO.new(non_ascii_parameters.to_json).length.to_s,
+                 @request.get_header("CONTENT_LENGTH"))
   end
 
   ActionDispatch::Session::AbstractStore::DEFAULT_OPTIONS.each_key do |option|
diff --git a/actionpack/test/controller/request_forgery_protection_test.rb b/actionpack/test/controller/request_forgery_protection_test.rb
index 90d5ab3c67..d645ddfdbe 100644
--- a/actionpack/test/controller/request_forgery_protection_test.rb
+++ b/actionpack/test/controller/request_forgery_protection_test.rb
@@ -92,7 +92,7 @@ class PrependProtectForgeryBaseController < ActionController::Base
     render inline: "OK"
   end
 
-  protected
+  private
 
     def add_called_callback(name)
       @called_callbacks ||= []
diff --git a/actionpack/test/controller/rescue_test.rb b/actionpack/test/controller/rescue_test.rb
index a98e6479b7..9ae22c4554 100644
--- a/actionpack/test/controller/rescue_test.rb
+++ b/actionpack/test/controller/rescue_test.rb
@@ -149,7 +149,7 @@ class RescueController < ActionController::Base
     raise RangeError
   end
 
-  protected
+  private
     def deny_access
       head :forbidden
     end
@@ -327,7 +327,7 @@ class RescueTest < ActionDispatch::IntegrationTest
       raise "b00m"
     end
 
-    protected
+    private
       def show_errors(exception)
         render plain: exception.message
       end
diff --git a/actionpack/test/controller/resources_test.rb b/actionpack/test/controller/resources_test.rb
index 0b3dc6c41f..fad34dacce 100644
--- a/actionpack/test/controller/resources_test.rb
+++ b/actionpack/test/controller/resources_test.rb
@@ -1089,7 +1089,7 @@ class ResourcesTest < ActionController::TestCase
     end
   end
 
-  protected
+  private
     def with_restful_routing(*args)
       options = args.extract_options!
       collection_methods = options.delete(:collection)
diff --git a/actionpack/test/controller/send_file_test.rb b/actionpack/test/controller/send_file_test.rb
index a28283f4d6..9e6b975fe2 100644
--- a/actionpack/test/controller/send_file_test.rb
+++ b/actionpack/test/controller/send_file_test.rb
@@ -241,10 +241,17 @@ class SendFileTest < ActionController::TestCase
     assert_equal "text/calendar; charset=utf-8", response.headers["Content-Type"]
   end
 
+  def test_send_file_charset_with_type_options_key_without_charset
+    @controller = SendFileWithActionControllerLive.new
+    @controller.options = { type: "image/png" }
+    response = process("file")
+    assert_equal "image/png", response.headers["Content-Type"]
+  end
+
   def test_send_file_charset_with_content_type_options_key
     @controller = SendFileWithActionControllerLive.new
     @controller.options = { content_type: "text/calendar" }
     response = process("file")
-    assert_equal "text/calendar; charset=utf-8", response.headers["Content-Type"]
+    assert_equal "text/calendar", response.headers["Content-Type"]
   end
 end
diff --git a/actionpack/test/controller/test_case_test.rb b/actionpack/test/controller/test_case_test.rb
index 05aa4ff6ad..874f9c3c42 100644
--- a/actionpack/test/controller/test_case_test.rb
+++ b/actionpack/test/controller/test_case_test.rb
@@ -100,11 +100,11 @@ HTML
     end
 
     def test_xml_output
-      response.content_type = "application/xml"
+      response.content_type = params[:response_as]
       render plain: <<XML
 <?xml version="1.0" encoding="UTF-8"?>
 <root>
-  <area>area is an empty tag in HTML, raising an error if not in xml mode</area>
+  <area><p>area is an empty tag in HTML, so it won't contain this content</p></area>
 </root>
 XML
     end
@@ -374,18 +374,18 @@ XML
     assert_equal "OK", @response.body
   end
 
-  def test_should_not_impose_childless_html_tags_in_xml
-    process :test_xml_output
+  def test_should_impose_childless_html_tags_in_html
+    process :test_xml_output, params: { response_as: "text/html" }
 
-    begin
-      $stderr = StringIO.new
-      assert_select "area" #This will cause a warning if content is processed as HTML
-      $stderr.rewind && err = $stderr.read
-    ensure
-      $stderr = STDERR
-    end
+    # <area> auto-closes, so the <p> becomes a sibling
+    assert_select "root > area + p"
+  end
+
+  def test_should_not_impose_childless_html_tags_in_xml
+    process :test_xml_output, params: { response_as: "application/xml" }
 
-    assert err.empty?, err.inspect
+    # <area> is not special, so the <p> is its child
+    assert_select "root > area > p"
   end
 
   def test_assert_generates
diff --git a/actionpack/test/controller/url_for_test.rb b/actionpack/test/controller/url_for_test.rb
index 4b6f33c545..382b4e273d 100644
--- a/actionpack/test/controller/url_for_test.rb
+++ b/actionpack/test/controller/url_for_test.rb
@@ -487,6 +487,27 @@ module AbstractController
         end
       end
 
+      def test_default_params_first_empty
+        with_routing do |set|
+          set.draw do
+            get "(:param1)/test(/:param2)" => "index#index",
+              defaults: {
+                param1: 1,
+                param2: 2
+              },
+              constraints: {
+                param1: /\d*/,
+                param2: /\d+/
+              }
+          end
+
+          kls = Class.new { include set.url_helpers }
+          kls.default_url_options[:host] = "www.basecamphq.com"
+
+          assert_equal "http://www.basecamphq.com/test", kls.new.url_for(controller: "index", param1: "1")
+        end
+      end
+
       private
         def extract_params(url)
           url.split("?", 2).last.split("&").sort
diff --git a/actionpack/test/dispatch/cookies_test.rb b/actionpack/test/dispatch/cookies_test.rb
index af3036d448..664faa31bb 100644
--- a/actionpack/test/dispatch/cookies_test.rb
+++ b/actionpack/test/dispatch/cookies_test.rb
@@ -272,6 +272,10 @@ class CookiesTest < ActionController::TestCase
     def noop
       head :ok
     end
+
+    def encrypted_cookie
+      cookies.encrypted["foo"]
+    end
   end
 
   tests TestController
@@ -940,8 +944,8 @@ class CookiesTest < ActionController::TestCase
     @request.headers["Cookie"] = "user_id=45"
     get :get_signed_cookie
 
-    assert_equal nil, @controller.send(:cookies).signed[:user_id]
-    assert_equal nil, @response.cookies["user_id"]
+    assert_nil @controller.send(:cookies).signed[:user_id]
+    assert_nil @response.cookies["user_id"]
   end
 
   def test_legacy_signed_cookie_is_treated_as_nil_by_encrypted_cookie_jar_if_tampered
@@ -951,8 +955,8 @@ class CookiesTest < ActionController::TestCase
     @request.headers["Cookie"] = "foo=baz"
     get :get_encrypted_cookie
 
-    assert_equal nil, @controller.send(:cookies).encrypted[:foo]
-    assert_equal nil, @response.cookies["foo"]
+    assert_nil @controller.send(:cookies).encrypted[:foo]
+    assert_nil @response.cookies["foo"]
   end
 
   def test_cookie_with_all_domain_option
@@ -1189,6 +1193,12 @@ class CookiesTest < ActionController::TestCase
     assert_equal "david", cookies[:user_name]
   end
 
+  def test_cookies_are_not_cleared
+    cookies.encrypted["foo"] = "bar"
+    get :noop
+    assert_equal "bar", @controller.encrypted_cookie
+  end
+
   private
     def assert_cookie_header(expected)
       header = @response.headers["Set-Cookie"]
diff --git a/actionpack/test/dispatch/request/multipart_params_parsing_test.rb b/actionpack/test/dispatch/request/multipart_params_parsing_test.rb
index eb4bb14ed1..01c5ff1429 100644
--- a/actionpack/test/dispatch/request/multipart_params_parsing_test.rb
+++ b/actionpack/test/dispatch/request/multipart_params_parsing_test.rb
@@ -129,7 +129,7 @@ class MultipartParamsParsingTest < ActionDispatch::IntegrationTest
     params = parse_multipart("none")
     assert_equal %w(submit-name), params.keys.sort
     assert_equal "Larry", params["submit-name"]
-    assert_equal nil, params["files"]
+    assert_nil params["files"]
   end
 
   test "parses empty upload file" do
diff --git a/actionpack/test/dispatch/request_test.rb b/actionpack/test/dispatch/request_test.rb
index 2f41851598..e11b93b4f0 100644
--- a/actionpack/test/dispatch/request_test.rb
+++ b/actionpack/test/dispatch/request_test.rb
@@ -18,7 +18,7 @@ class BaseRequestTest < ActiveSupport::TestCase
     ActionDispatch::Http::URL.url_for(options)
   end
 
-  protected
+  private
     def stub_request(env = {})
       ip_spoofing_check = env.key?(:ip_spoofing_check) ? env.delete(:ip_spoofing_check) : true
       @trusted_proxies ||= nil
@@ -94,13 +94,13 @@ class RequestIP < BaseRequestTest
     assert_equal "3.4.5.6", request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "unknown,192.168.0.1"
-    assert_equal nil, request.remote_ip
+    assert_nil request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "9.9.9.9, 3.4.5.6, 172.31.4.4, 10.0.0.1"
     assert_equal "3.4.5.6", request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "not_ip_address"
-    assert_equal nil, request.remote_ip
+    assert_nil request.remote_ip
   end
 
   test "remote ip spoof detection" do
@@ -154,7 +154,7 @@ class RequestIP < BaseRequestTest
     assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "unknown,::1"
-    assert_equal nil, request.remote_ip
+    assert_nil request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "2001:0db8:85a3:0000:0000:8a2e:0370:7334, fe80:0000:0000:0000:0202:b3ff:fe1e:8329, ::1, fc00::, fc01::, fdff"
     assert_equal "fe80:0000:0000:0000:0202:b3ff:fe1e:8329", request.remote_ip
@@ -163,7 +163,7 @@ class RequestIP < BaseRequestTest
     assert_equal "FE00::", request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "not_ip_address"
-    assert_equal nil, request.remote_ip
+    assert_nil request.remote_ip
   end
 
   test "remote ip v6 spoof detection" do
@@ -200,7 +200,7 @@ class RequestIP < BaseRequestTest
     assert_equal "3.4.5.6", request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "67.205.106.73,unknown"
-    assert_equal nil, request.remote_ip
+    assert_nil request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "9.9.9.9, 3.4.5.6, 10.0.0.1, 67.205.106.73"
     assert_equal "3.4.5.6", request.remote_ip
@@ -222,7 +222,7 @@ class RequestIP < BaseRequestTest
     assert_equal "::1", request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "unknown,fe80:0000:0000:0000:0202:b3ff:fe1e:8329"
-    assert_equal nil, request.remote_ip
+    assert_nil request.remote_ip
 
     request = stub_request "HTTP_X_FORWARDED_FOR" => "fe80:0000:0000:0000:0202:b3ff:fe1e:8329,2001:0db8:85a3:0000:0000:8a2e:0370:7334"
     assert_equal "2001:0db8:85a3:0000:0000:8a2e:0370:7334", request.remote_ip
@@ -345,7 +345,7 @@ class RequestPort < BaseRequestTest
 
   test "optional port" do
     request = stub_request "HTTP_HOST" => "www.example.org:80"
-    assert_equal nil, request.optional_port
+    assert_nil request.optional_port
 
     request = stub_request "HTTP_HOST" => "www.example.org:8080"
     assert_equal 8080, request.optional_port
@@ -537,7 +537,7 @@ class RequestCGI < BaseRequestTest
 
     assert_equal "Basic", request.auth_type
     assert_equal 0, request.content_length
-    assert_equal nil, request.content_mime_type
+    assert_nil request.content_mime_type
     assert_equal "CGI/1.1", request.gateway_interface
     assert_equal "*/*", request.accept
     assert_equal "UTF-8", request.accept_charset
@@ -957,7 +957,7 @@ class RequestMimeType < BaseRequestTest
   end
 
   test "no content type" do
-    assert_equal nil, stub_request.content_mime_type
+    assert_nil stub_request.content_mime_type
   end
 
   test "content type is XML" do
@@ -978,7 +978,7 @@ class RequestMimeType < BaseRequestTest
       "HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"
     )
 
-    assert_equal nil, request.negotiate_mime([Mime[:xml], Mime[:json]])
+    assert_nil request.negotiate_mime([Mime[:xml], Mime[:json]])
     assert_equal Mime[:html], request.negotiate_mime([Mime[:xml], Mime[:html]])
     assert_equal Mime[:html], request.negotiate_mime([Mime[:xml], Mime::ALL])
   end
@@ -1192,7 +1192,7 @@ class RequestEtag < BaseRequestTest
   test "doesn't match absent If-None-Match" do
     request = stub_request
 
-    assert_equal nil, request.if_none_match
+    assert_nil request.if_none_match
     assert_equal [], request.if_none_match_etags
 
     assert_not request.etag_matches?("foo")
diff --git a/actionpack/test/dispatch/response_test.rb b/actionpack/test/dispatch/response_test.rb
index 400af42bac..7433c5ce0c 100644
--- a/actionpack/test/dispatch/response_test.rb
+++ b/actionpack/test/dispatch/response_test.rb
@@ -74,7 +74,7 @@ class ResponseTest < ActiveSupport::TestCase
     @response.body = "Hello, World!"
 
     # even though there's no explicitly set content-type,
-    assert_equal nil, @response.content_type
+    assert_nil @response.content_type
 
     # after the action reads back @response.body,
     assert_equal "Hello, World!", @response.body
@@ -110,6 +110,11 @@ class ResponseTest < ActiveSupport::TestCase
     assert_equal "application/aaron", @response.content_type
   end
 
+  def test_empty_content_type_returns_nil
+    @response.headers["Content-Type"] = ""
+    assert_nil @response.content_type
+  end
+
   test "simple output" do
     @response.body = "Hello, World!"
 
diff --git a/actionpack/test/dispatch/routing/ipv6_redirect_test.rb b/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
index 4987ed84e4..179aee9ba7 100644
--- a/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
+++ b/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
@@ -7,7 +7,7 @@ class IPv6IntegrationTest < ActionDispatch::IntegrationTest
   class ::BadRouteRequestController < ActionController::Base
     include Routes.url_helpers
     def index
-      render text: foo_path
+      render plain: foo_path
     end
 
     def foo
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index 92d323f292..474d053af6 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -4189,7 +4189,7 @@ class TestConstraintsAccessingParameters < ActionDispatch::IntegrationTest
 
   test "parameters are reset between constraint checks" do
     get "/bar"
-    assert_equal nil, @request.params[:foo]
+    assert_nil @request.params[:foo]
     assert_equal "bar", @request.params[:bar]
   end
 end
diff --git a/actionpack/test/dispatch/session/cache_store_test.rb b/actionpack/test/dispatch/session/cache_store_test.rb
index a60629a7ee..859059063f 100644
--- a/actionpack/test/dispatch/session/cache_store_test.rb
+++ b/actionpack/test/dispatch/session/cache_store_test.rb
@@ -142,20 +142,20 @@ class CacheStoreTest < ActionDispatch::IntegrationTest
 
       get "/get_session_value"
       assert_response :success
-      assert_equal nil, headers["Set-Cookie"], "should not resend the cookie again if session_id cookie is already exists"
+      assert_nil headers["Set-Cookie"], "should not resend the cookie again if session_id cookie is already exists"
     end
   end
 
   def test_prevents_session_fixation
     with_test_route_set do
-      assert_equal nil, @cache.read("_session_id:0xhax")
+      assert_nil @cache.read("_session_id:0xhax")
 
       cookies["_session_id"] = "0xhax"
       get "/set_session_value"
 
       assert_response :success
       assert_not_equal "0xhax", cookies["_session_id"]
-      assert_equal nil, @cache.read("_session_id:0xhax")
+      assert_nil @cache.read("_session_id:0xhax")
       assert_equal({ "foo" => "bar" }, @cache.read("_session_id:#{cookies['_session_id']}"))
     end
   end
diff --git a/actionpack/test/dispatch/session/cookie_store_test.rb b/actionpack/test/dispatch/session/cookie_store_test.rb
index 013d289c6d..2a1053be16 100644
--- a/actionpack/test/dispatch/session/cookie_store_test.rb
+++ b/actionpack/test/dispatch/session/cookie_store_test.rb
@@ -108,7 +108,7 @@ class CookieStoreTest < ActionDispatch::IntegrationTest
     with_test_route_set(secure: true) do
       get "/set_session_value"
       assert_response :success
-      assert_equal nil, headers["Set-Cookie"]
+      assert_nil headers["Set-Cookie"]
     end
   end
 
@@ -169,7 +169,7 @@ class CookieStoreTest < ActionDispatch::IntegrationTest
     with_test_route_set do
       get "/no_session_access"
       assert_response :success
-      assert_equal nil, headers["Set-Cookie"]
+      assert_nil headers["Set-Cookie"]
     end
   end
 
@@ -179,7 +179,7 @@ class CookieStoreTest < ActionDispatch::IntegrationTest
         "fef868465920f415f2c0652d6910d3af288a0367"
       get "/no_session_access"
       assert_response :success
-      assert_equal nil, headers["Set-Cookie"]
+      assert_nil headers["Set-Cookie"]
     end
   end
 
diff --git a/actionpack/test/dispatch/session/mem_cache_store_test.rb b/actionpack/test/dispatch/session/mem_cache_store_test.rb
index c2d0719b4e..121e9ebef7 100644
--- a/actionpack/test/dispatch/session/mem_cache_store_test.rb
+++ b/actionpack/test/dispatch/session/mem_cache_store_test.rb
@@ -157,7 +157,7 @@ class MemCacheStoreTest < ActionDispatch::IntegrationTest
 
         get "/get_session_value"
         assert_response :success
-        assert_equal nil, headers["Set-Cookie"], "should not resend the cookie again if session_id cookie is already exists"
+        assert_nil headers["Set-Cookie"], "should not resend the cookie again if session_id cookie is already exists"
       end
     rescue Dalli::RingError => ex
       skip ex.message, ex.backtrace
diff --git a/actionpack/test/dispatch/static_test.rb b/actionpack/test/dispatch/static_test.rb
index 3facbf59c2..d8bc96e3e0 100644
--- a/actionpack/test/dispatch/static_test.rb
+++ b/actionpack/test/dispatch/static_test.rb
@@ -177,9 +177,9 @@ module StaticTests
     last_modified = File.mtime(File.join(@root, "#{file_name}.gz"))
     response = get(file_name, "HTTP_ACCEPT_ENCODING" => "gzip", "HTTP_IF_MODIFIED_SINCE" => last_modified.httpdate)
     assert_equal 304, response.status
-    assert_equal nil, response.headers["Content-Type"]
-    assert_equal nil, response.headers["Content-Encoding"]
-    assert_equal nil, response.headers["Vary"]
+    assert_nil response.headers["Content-Type"]
+    assert_nil response.headers["Content-Encoding"]
+    assert_nil response.headers["Vary"]
   end
 
   def test_serves_files_with_headers
diff --git a/actionpack/test/dispatch/test_request_test.rb b/actionpack/test/dispatch/test_request_test.rb
index b479af781d..85a6df4975 100644
--- a/actionpack/test/dispatch/test_request_test.rb
+++ b/actionpack/test/dispatch/test_request_test.rb
@@ -30,7 +30,7 @@ class TestRequestTest < ActiveSupport::TestCase
     req = ActionDispatch::TestRequest.create({})
 
     assert_equal({}, req.cookies)
-    assert_equal nil, req.env["HTTP_COOKIE"]
+    assert_nil req.env["HTTP_COOKIE"]
 
     req.cookie_jar["user_name"] = "david"
     assert_cookies({ "user_name" => "david" }, req.cookie_jar)
diff --git a/actionpack/test/journey/route_test.rb b/actionpack/test/journey/route_test.rb
index d2a8163ffb..8fd73970b8 100644
--- a/actionpack/test/journey/route_test.rb
+++ b/actionpack/test/journey/route_test.rb
@@ -96,7 +96,7 @@ module ActionDispatch
         path = Path::Pattern.from_string "/:controller(/:action(/:id))(.:format)"
         generic = Route.build "name", nil, path, constraints, [], {}
 
-        knowledge = { id: 20, controller: "pages", action: "show" }
+        knowledge = { "id" => true, "controller" => true, "action" => true }
 
         routes = [specific, generic]