3 files changed, 25 insertions, 1 deletions
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 68a526eccb..ca8066cd82 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -213,6 +213,7 @@ module ActionController
       Renderers::All,
       ConditionalGet,
       EtagWithTemplateDigest,
+      EtagWithFlash,
       Caching,
       MimeResponds,
       ImplicitRender,
diff --git a/actionpack/lib/action_controller/metal/etag_with_flash.rb b/actionpack/lib/action_controller/metal/etag_with_flash.rb
new file mode 100644
index 0000000000..474d75f02e
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/etag_with_flash.rb
@@ -0,0 +1,16 @@
+module ActionController
+  # When you're using the flash, it's generally used as a conditional on the view.
+  # This means the content of the view depends on the flash. Which in turn means
+  # that the etag for a response should be computed with the content of the flash
+  # in mind. This does that by including the content of the flash as a component
+  # in the etag that's generated for a response.
+  module EtagWithFlash
+    extend ActiveSupport::Concern
+
+    include ActionController::ConditionalGet
+
+    included do
+      etag { flash unless flash.empty? }
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index 83c32136dd..11a6cf8e15 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -449,6 +449,8 @@ module ActionController
       # - +session+: A hash of parameters to store in the session. This may be +nil+.
       # - +flash+: A hash of parameters to store in the flash. This may be +nil+.
       # - +format+: Request format. Defaults to +nil+. Can be string or symbol.
+      # - +as+: Content type. Defaults to +nil+. Must be a symbol that corresponds
+      #   to a mime type.
       #
       # Example calling +create+ action and sending two params:
       #
@@ -469,7 +471,7 @@ module ActionController
         check_required_ivars
 
         if kwarg_request?(args)
-          parameters, session, body, flash, http_method, format, xhr = args[0].values_at(:params, :session, :body, :flash, :method, :format, :xhr)
+          parameters, session, body, flash, http_method, format, xhr, as = args[0].values_at(:params, :session, :body, :flash, :method, :format, :xhr, :as)
         else
           http_method, parameters, session, flash = args
           format = nil
@@ -514,6 +516,11 @@ module ActionController
 
         @request.set_header "REQUEST_METHOD", http_method
 
+        if as
+          @request.content_type = Mime[as].to_s
+          format ||= as
+        end
+
         parameters = parameters.symbolize_keys
 
         generated_extras = @routes.generate_extras(parameters.merge(controller: controller_class_name, action: action.to_s))