Encapsulate serialization in ActiveModel::SerializableResource

Usage: ActiveModel::SerializableResource.serialize(resource, options)

test/test_helper.rb

@@ -13,6 +13,55 @@ Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
 
 require 'active_model_serializers'
 
+# Use cleaner stream testing interface from Rails 5 if available
+# see https://github.com/rails/rails/blob/29959eb59d/activesupport/lib/active_support/testing/stream.rb
+begin
+  require "active_support/testing/stream"
+rescue LoadError
+  module ActiveSupport
+    module Testing
+      module Stream #:nodoc:
+        private
+
+        def silence_stream(stream)
+          old_stream = stream.dup
+          stream.reopen(IO::NULL)
+          stream.sync = true
+          yield
+        ensure
+          stream.reopen(old_stream)
+          old_stream.close
+        end
+
+        def quietly
+          silence_stream(STDOUT) do
+            silence_stream(STDERR) do
+              yield
+            end
+          end
+        end
+
+        def capture(stream)
+          stream = stream.to_s
+          captured_stream = Tempfile.new(stream)
+          stream_io = eval("$#{stream}")
+          origin_stream = stream_io.dup
+          stream_io.reopen(captured_stream)
+
+          yield
+
+          stream_io.rewind
+          return captured_stream.read
+        ensure
+          captured_stream.close
+          captured_stream.unlink
+          stream_io.reopen(origin_stream)
+        end
+      end
+    end
+  end
+end
+
 class Foo < Rails::Application
   if Rails::VERSION::MAJOR >= 4
     config.eager_load = false