3 files changed, 14 insertions, 10 deletions
diff --git a/actionpack/test/controller/required_params_test.rb b/actionpack/test/controller/required_params_test.rb
index 661bcb3945..2898adee72 100644
--- a/actionpack/test/controller/required_params_test.rb
+++ b/actionpack/test/controller/required_params_test.rb
@@ -11,20 +11,17 @@ class ActionControllerRequiredParamsTest < ActionController::TestCase
   tests BooksController
 
   test "missing required parameters will raise exception" do
-    post :create, { magazine: { name: "Mjallo!" } }
-    assert_response :bad_request
+    assert_raise (ActionController::ParameterMissing) do
+      post :create, { magazine: { name: "Mjallo!" } }
+    end
 
-    post :create, { book: { title: "Mjallo!" } }
-    assert_response :bad_request
+    assert_raise (ActionController::ParameterMissing) do
+      post :create, { book: { title: "Mjallo!" } }
+    end
   end
 
   test "required parameters that are present will not raise" do
     post :create, { book: { name: "Mjallo!" } }
     assert_response :ok
   end
-
-  test "missing parameters will be mentioned in the return" do
-    post :create, { magazine: { name: "Mjallo!" } }
-    assert_equal "Required parameter missing: book", response.body
-  end
 end
diff --git a/actionpack/test/dispatch/best_standards_support_test.rb b/actionpack/test/dispatch/best_standards_support_test.rb
index 0737c40a39..551bb9621a 100644
--- a/actionpack/test/dispatch/best_standards_support_test.rb
+++ b/actionpack/test/dispatch/best_standards_support_test.rb
@@ -16,9 +16,10 @@ class BestStandardsSupportTest < ActiveSupport::TestCase
     assert_equal nil, headers["X-UA-Compatible"]
   end
 
-  def test_appends_to_app_headers
+  def test_appends_to_app_headers_without_duplication_after_multiple_requests
     app_headers = { "X-UA-Compatible" => "requiresActiveX=true" }
     _, headers, _ = app(true, app_headers).call({})
+    _, headers, _ = app(true, app_headers).call({})
 
     expects = "requiresActiveX=true,IE=Edge,chrome=1"
     assert_equal expects, headers["X-UA-Compatible"]
diff --git a/actionpack/test/dispatch/debug_exceptions_test.rb b/actionpack/test/dispatch/debug_exceptions_test.rb
index 1319eba9ac..6035f0361e 100644
--- a/actionpack/test/dispatch/debug_exceptions_test.rb
+++ b/actionpack/test/dispatch/debug_exceptions_test.rb
@@ -39,6 +39,8 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
         raise ActionController::BadRequest
       when "/missing_keys"
         raise ActionController::UrlGenerationError, "No route matches"
+      when "/parameter_missing"
+        raise ActionController::ParameterMissing, :missing_param_key
       else
         raise "puke!"
       end
@@ -114,6 +116,10 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
     get "/bad_request", {}, {'action_dispatch.show_exceptions' => true}
     assert_response 400
     assert_match(/ActionController::BadRequest/, body)
+
+    get "/parameter_missing", {}, {'action_dispatch.show_exceptions' => true}
+    assert_response 400
+    assert_match(/ActionController::ParameterMissing/, body)
   end
 
   test "does not show filtered parameters" do