* Do not ingerit array serializer from Serializer

* Tests for ArraySerializer

lib/active_model/serializer/array_serializer.rb

@@ -1,13 +1,13 @@
 module ActiveModel
   class Serializer
-    class ArraySerializer < Serializer
+    class ArraySerializer
       include Enumerable
-      delegate :each, to: :object
+      delegate :each, to: :@objects
 
-      def initialize(object)
-        @object = object.map do |item|
-          serializer_class = ActiveModel::Serializer.serializer_for(item)
-          serializer_class.new(item)
+      def initialize(objects, options = {})
+        @objects = objects.map do |object|
+          serializer_class = ActiveModel::Serializer.serializer_for(object)
+          serializer_class.new(object)
         end
       end
     end

test/array_serializer_test.rb

@@ -0,0 +1,27 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class ArraySerializerTest < Minitest::Test
+      def setup
+        @comment = Comment.new
+        @post= Post.new
+        @serializer = ArraySerializer.new([@comment, @post])
+      end
+
+      def test_respond_to_each
+        assert_respond_to @serializer, :each
+      end
+
+      def test_each_object_should_be_serializer_with_appropriate_serializer
+        serializers =  @serializer.to_a
+
+        assert_kind_of CommentSerializer, serializers.first
+        assert_kind_of Comment, serializers.first.object
+
+        assert_kind_of PostSerializer, serializers.last
+        assert_kind_of Post, serializers.last.object
+      end
+    end
+  end
+end