2 files changed, 3 insertions, 4 deletions
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
index a5e7a8c715..40d38c59d6 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -4,11 +4,9 @@ module ActionDispatch
   module Assertions
     # A small suite of assertions that test responses from \Rails applications.
     module ResponseAssertions
-      extend ActiveSupport::Concern
-
       # Asserts that the response is one of the following types:
       #
-      # * <tt>:success</tt>   - Status code was 200
+      # * <tt>:success</tt>   - Status code was in the 200-299 range
       # * <tt>:redirect</tt>  - Status code was in the 300-399 range
       # * <tt>:missing</tt>   - Status code was 404
       # * <tt>:error</tt>     - Status code was in the 500-599 range
@@ -83,7 +81,7 @@ module ActionDispatch
             refer
           else
             @controller.url_for(fragment)
-          end.gsub(/[\0\r\n]/, '')
+          end.delete("\0\r\n")
         end
     end
   end
diff --git a/actionpack/lib/action_dispatch/testing/assertions/selector.rb b/actionpack/lib/action_dispatch/testing/assertions/selector.rb
index 8eed85bce2..ea1ed20f3c 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/selector.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/selector.rb
@@ -269,6 +269,7 @@ module ActionDispatch
               end
             end
             text.strip! unless NO_STRIP.include?(match.name)
+            text.sub!(/\A\n/, '') if match.name == "textarea"
             unless match_with.is_a?(Regexp) ? (text =~ match_with) : (text == match_with.to_s)
               content_mismatch ||= sprintf("<%s> expected but was\n<%s>.", match_with, text)
               true