2 files changed, 23 insertions, 18 deletions
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
index b64f660ec5..b8d395854c 100644
--- a/actionpack/lib/action_dispatch/http/mime_type.rb
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -47,15 +47,10 @@ module Mime
     def const_missing(sym)
       ext = sym.downcase
       if Mime[ext]
-        ActiveSupport::Deprecation.warn <<-eow
-Accessing mime types via constants is deprecated.  Please change:
-
-  `Mime::#{sym}`
-
-to:
-
-  `Mime[:#{ext}]`
-        eow
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          Accessing mime types via constants is deprecated.
+          Please change `Mime::#{sym}` to `Mime[:#{ext}]`.
+        MSG
         Mime[ext]
       else
         super
@@ -65,15 +60,10 @@ to:
     def const_defined?(sym, inherit = true)
       ext = sym.downcase
       if Mime[ext]
-        ActiveSupport::Deprecation.warn <<-eow
-Accessing mime types via constants is deprecated.  Please change:
-
-  `Mime.const_defined?(#{sym})`
-
-to:
-
-  `Mime[:#{ext}]`
-        eow
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          Accessing mime types via constants is deprecated.
+          Please change `Mime.const_defined?(#{sym})` to `Mime[:#{ext}]`.
+        MSG
         true
       else
         super
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
index eab20b075d..5af052afb4 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -27,6 +27,8 @@ module ActionDispatch
       #   # Asserts that the response code was status code 401 (unauthorized)
       #   assert_response 401
       def assert_response(type, message = nil)
+        message ||= generate_response_message(type)
+
         if Symbol === type
           if [:success, :missing, :redirect, :error].include?(type)
             assert_predicate @response, RESPONSE_PREDICATES[type], message
@@ -82,6 +84,19 @@ module ActionDispatch
             handle._compute_redirect_to_location(@request, fragment)
           end
         end
+
+        def generate_response_message(type)
+          message = "Expected response to be a <#{type}>, but was"
+
+          if @response.redirection?
+            redirect_is = normalize_argument_to_redirection(@response.location)
+            message << " a redirect to <#{redirect_is}>"
+          else
+            message << " <#{@response.response_code}>"
+          end
+
+          message
+        end
     end
   end
 end