1 files changed, 45 insertions, 20 deletions
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
index 13a72220b3..98b1965d22 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -1,8 +1,16 @@
+# frozen_string_literal: true
 
 module ActionDispatch
   module Assertions
     # A small suite of assertions that test responses from \Rails applications.
     module ResponseAssertions
+      RESPONSE_PREDICATES = { # :nodoc:
+        success:  :successful?,
+        missing:  :not_found?,
+        redirect: :redirection?,
+        error:    :server_error?,
+      }
+
       # Asserts that the response is one of the following types:
       #
       # * <tt>:success</tt>   - Status code was in the 200-299 range
@@ -14,45 +22,37 @@ module ActionDispatch
       # or its symbolic equivalent <tt>assert_response(:not_implemented)</tt>.
       # See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list.
       #
-      #   # assert that the response was a redirection
+      #   # Asserts that the response was a redirection
       #   assert_response :redirect
       #
-      #   # assert that the response code was status code 401 (unauthorized)
+      #   # Asserts that the response code was status code 401 (unauthorized)
       #   assert_response 401
       def assert_response(type, message = nil)
-        message ||= "Expected response to be a <#{type}>, but was <#{@response.response_code}>"
+        message ||= generate_response_message(type)
 
-        if Symbol === type
-          if [:success, :missing, :redirect, :error].include?(type)
-            assert @response.send("#{type}?"), message
-          else
-            code = Rack::Utils::SYMBOL_TO_STATUS_CODE[type]
-            if code.nil?
-              raise ArgumentError, "Invalid response type :#{type}"
-            end
-            assert_equal code, @response.response_code, message
-          end
+        if RESPONSE_PREDICATES.keys.include?(type)
+          assert @response.send(RESPONSE_PREDICATES[type]), message
         else
-          assert_equal type, @response.response_code, message
+          assert_equal AssertionResponse.new(type).code, @response.response_code, message
         end
       end
 
-      # Assert that the redirection options passed in match those of the redirect called in the latest action.
+      # Asserts that the redirection options passed in match those of the redirect called in the latest action.
       # This match can be partial, such that <tt>assert_redirected_to(controller: "weblog")</tt> will also
       # match the redirection of <tt>redirect_to(controller: "weblog", action: "show")</tt> and so on.
       #
-      #   # assert that the redirection was to the "index" action on the WeblogController
+      #   # Asserts that the redirection was to the "index" action on the WeblogController
       #   assert_redirected_to controller: "weblog", action: "index"
       #
-      #   # assert that the redirection was to the named route login_url
+      #   # Asserts that the redirection was to the named route login_url
       #   assert_redirected_to login_url
       #
-      #   # assert that the redirection was to the url for @customer
+      #   # Asserts that the redirection was to the URL for @customer
       #   assert_redirected_to @customer
       #
-      #   # asserts that the redirection matches the regular expression
+      #   # Asserts that the redirection matches the regular expression
       #   assert_redirected_to %r(\Ahttp://example.org)
-      def assert_redirected_to(options = {}, message=nil)
+      def assert_redirected_to(options = {}, message = nil)
         assert_response(:redirect, message)
         return true if options === @response.location
 
@@ -77,6 +77,31 @@ module ActionDispatch
             handle._compute_redirect_to_location(@request, fragment)
           end
         end
+
+        def generate_response_message(expected, actual = @response.response_code)
+          "Expected response to be a <#{code_with_name(expected)}>,"\
+          " but was a <#{code_with_name(actual)}>"
+            .dup.concat(location_if_redirected).concat(response_body_if_short)
+        end
+
+        def response_body_if_short
+          return "" if @response.body.size > 500
+          "\nResponse body: #{@response.body}"
+        end
+
+        def location_if_redirected
+          return "" unless @response.redirection? && @response.location.present?
+          location = normalize_argument_to_redirection(@response.location)
+          " redirect to <#{location}>"
+        end
+
+        def code_with_name(code_or_name)
+          if RESPONSE_PREDICATES.values.include?("#{code_or_name}?".to_sym)
+            code_or_name = RESPONSE_PREDICATES.invert["#{code_or_name}?".to_sym]
+          end
+
+          AssertionResponse.new(code_or_name).code_and_name
+        end
     end
   end
 end