1 files changed, 12 insertions, 3 deletions
diff --git a/actionpack/test/controller/test_case_test.rb b/actionpack/test/controller/test_case_test.rb
index 06bf9dec74..e50373a0cc 100644
--- a/actionpack/test/controller/test_case_test.rb
+++ b/actionpack/test/controller/test_case_test.rb
@@ -75,7 +75,7 @@ class TestCaseTest < ActionController::TestCase
     end
 
     def test_headers
-      render plain: request.headers.env.to_json
+      render plain: ::JSON.dump(request.headers.env)
     end
 
     def test_html_output
@@ -139,7 +139,7 @@ XML
 
     def delete_cookie
       cookies.delete("foo")
-      head :ok
+      render plain: 'ok'
     end
 
     def test_without_body
@@ -974,6 +974,11 @@ class ResponseDefaultHeadersTest < ActionController::TestCase
       headers.delete params[:header]
       head :ok, 'C' => '3'
     end
+
+    # Render a head response, but don't touch default headers
+    def leave_alone
+      head :ok
+    end
   end
 
   def before_setup
@@ -999,9 +1004,13 @@ class ResponseDefaultHeadersTest < ActionController::TestCase
   end
 
   test "response contains default headers" do
+    get :leave_alone
+
     # Response headers start out with the defaults
-    assert_equal @defaults, response.headers
+    assert_equal @defaults.merge('Content-Type' => 'text/html'), response.headers
+  end
 
+  test "response deletes a default header" do
     get :remove_header, params: { header: 'A' }
     assert_response :ok