Add an assertion.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55582 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/net/http/test_http.rb

@@ -320,6 +320,9 @@ module TestNetHTTP_version_1_1_methods
       assert_raise(ArgumentError) do
         http.get("\r")
       end
+      assert_raise(ArgumentError) do
+        http.get("\n")
+      end
     }
   end