3 files changed, 21 insertions, 1 deletions
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
index 72163ccd5e..cb282d4330 100644
--- a/actionpack/test/controller/integration_test.rb
+++ b/actionpack/test/controller/integration_test.rb
@@ -335,6 +335,18 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
     end
   end
 
+  def test_redirect_reset_html_document
+    with_test_route_set do
+      get "/redirect"
+      previous_html_document = html_document
+
+      follow_redirect!
+
+      assert_response :ok
+      refute_same previous_html_document, html_document
+    end
+  end
+
   def test_xml_http_request_get
     with_test_route_set do
       get "/get", xhr: true
diff --git a/actionpack/test/controller/parameters/mutators_test.rb b/actionpack/test/controller/parameters/mutators_test.rb
index 2c36f488c6..3fe7340782 100644
--- a/actionpack/test/controller/parameters/mutators_test.rb
+++ b/actionpack/test/controller/parameters/mutators_test.rb
@@ -35,7 +35,7 @@ class ParametersMutatorsTest < ActiveSupport::TestCase
   end
 
   test "delete returns nil when the key is not present" do
-    assert_equal nil, @params[:person].delete(:first_name)
+    assert_nil @params[:person].delete(:first_name)
   end
 
   test "delete returns the value of the given block when the key is not present" do
diff --git a/actionpack/test/controller/params_wrapper_test.rb b/actionpack/test/controller/params_wrapper_test.rb
index 2a41d57b26..4cbb28ef60 100644
--- a/actionpack/test/controller/params_wrapper_test.rb
+++ b/actionpack/test/controller/params_wrapper_test.rb
@@ -170,6 +170,14 @@ class ParamsWrapperTest < ActionController::TestCase
     end
   end
 
+  def test_no_double_wrap_if_key_exists_and_value_is_nil
+    with_default_wrapper_options do
+      @request.env["CONTENT_TYPE"] = "application/json"
+      post :parse, params: { "user" => nil }
+      assert_parameters("user" => nil)
+    end
+  end
+
   def test_nested_params
     with_default_wrapper_options do
       @request.env["CONTENT_TYPE"] = "application/json"