Test::Unit assert_serializer implemented

So you can assert specific serializer to be used.

test/integration/action_controller/test_case_test.rb

@@ -0,0 +1,55 @@
+require 'test_helper'
+
+module ActionController
+  module SerializationsAssertions
+    class RenderSerializerTest < ActionController::TestCase
+      class MyController < ActionController::Base
+        def render_using_serializer
+          render json: Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
+        end
+
+        def render_text
+          render text: 'ok'
+        end
+      end
+
+      tests MyController
+
+      def test_supports_specifying_serializers_with_a_regexp
+        get :render_using_serializer
+        assert_serializer %r{\AProfile.+\Z}
+      end
+
+      def test_supports_specifying_serializers_with_a_string
+        get :render_using_serializer
+        assert_serializer 'ProfileSerializer'
+      end
+
+      def test_supports_specifying_serializers_with_a_symbol
+        get :render_using_serializer
+        assert_serializer :profile_serializer
+      end
+
+      def test_supports_specifying_serializers_with_a_nil
+        get :render_text
+        assert_serializer nil
+      end
+
+      def test_raises_descriptive_error_message_when_serializer_was_not_rendered
+        get :render_using_serializer
+        e = assert_raise ActiveSupport::TestCase::Assertion do
+          assert_serializer 'PostSerializer'
+        end
+        assert_match 'expecting <"PostSerializer"> but rendering with <["ProfileSerializer"]>', e.message
+      end
+
+      def test_raises_argument_error_when_asserting_with_invalid_object
+        get :render_using_serializer
+        e = assert_raise ArgumentError do
+          assert_serializer OpenStruct.new
+        end
+        assert_match 'assert_serializer only accepts a String, Symbol, Regexp, or nil', e.message
+      end
+    end
+  end
+end