diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index fa0e3dc65..973911d3f 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -23,9 +23,9 @@ class << self
     end
 
     def self.inherited(base)
-      base._attributes = self._attributes.try(:dup)  || []
+      base._attributes = self._attributes.try(:dup) || []
       base._attributes_keys = self._attributes_keys.try(:dup) || {}
-      base._associations = self._associations.try(:dup) || {}
+      base._associations = self._associations.try(:dup) || []
       base._urls = []
       serializer_file = File.open(caller.first[/^[^:]+/])
       base._cache_digest = Digest::MD5.hexdigest(serializer_file.read)
@@ -45,7 +45,7 @@ def self.attributes(*attrs)
 
     def self.attribute(attr, options = {})
       key = options.fetch(:key, attr)
-      @_attributes_keys[attr] = {key: key} if key != attr
+      @_attributes_keys[attr] = { key: key } if key != attr
       @_attributes << key unless @_attributes.include?(key)
       define_method key do
         object.read_attribute_for_serialization(attr)
@@ -58,13 +58,17 @@ def self.fragmented(serializer)
 
     # Enables a serializer to be automatically cached
     def self.cache(options = {})
-      @_cache         = ActionController::Base.cache_store if Rails.configuration.action_controller.perform_caching
-      @_cache_key     = options.delete(:key)
-      @_cache_only    = options.delete(:only)
-      @_cache_except  = options.delete(:except)
+      @_cache = ActionController::Base.cache_store if Rails.configuration.action_controller.perform_caching
+      @_cache_key = options.delete(:key)
+      @_cache_only = options.delete(:only)
+      @_cache_except = options.delete(:except)
       @_cache_options = (options.empty?) ? nil : options
     end
 
+    Association = Struct.new(:name, :options)
+    SingularAssociation = Class.new(Association)
+    CollectionAssociation = Class.new(Association)
+
     # Defines an association in the object should be rendered.
     #
     # The serializer object should implement the association name
@@ -72,7 +76,9 @@ def self.cache(options = {})
     # with the association name does not exist, the association name is
     # dispatched to the serialized object.
     def self.has_many(*attrs)
-      associate(:has_many, attrs)
+      associate attrs do |name, options|
+        CollectionAssociation.new(name, options)
+      end
     end
 
     # Defines an association in the object that should be rendered.
@@ -82,7 +88,9 @@ def self.has_many(*attrs)
     # with the association name does not exist, the association name is
     # dispatched to the serialized object.
     def self.belongs_to(*attrs)
-      associate(:belongs_to, attrs)
+      associate attrs do |name, options|
+        SingularAssociation.new(name, options)
+      end
     end
 
     # Defines an association in the object should be rendered.
@@ -92,21 +100,24 @@ def self.belongs_to(*attrs)
     # with the association name does not exist, the association name is
     # dispatched to the serialized object.
     def self.has_one(*attrs)
-      associate(:has_one, attrs)
+      associate attrs do |name, options|
+        SingularAssociation.new(name, options)
+      end
     end
 
-    def self.associate(type, attrs) #:nodoc:
+    # has_one :author, :image, only: :object
+    def self.associate(attrs, &block) #:nodoc:
       options = attrs.extract_options!
       self._associations = _associations.dup
 
-      attrs.each do |attr|
-        unless method_defined?(attr)
-          define_method attr do
-            object.send attr
+      attrs.each do |name|
+        unless method_defined?(name)
+          define_method name do
+            object.send name
           end
         end
 
-        self._associations[attr] = {type: type, association_options: options}
+        self._associations << block.call(name, options)
       end
     end
 
@@ -198,31 +209,50 @@ def attributes(options = {})
       end
     end
 
+    def associations
+      Enumerator.new do |y|
+        self.class._associations.dup.each do |association|
+          y.yield association
+        end
+      end
+    end
+
+    # @return [Enumerable]
+    #
+    def associations
+
+    end
+    require 'pp'
     def each_association(&block)
       return unless object
       return unless block_given?
 
-      self.class._associations.dup.each do |name, association_options|
-        association_value = send(name)
+      # self._associations[attr] = {type: type, association_options: options}
+      # @param [Hash<Symbol,Hash<Symbol,Object>] before
+      #
+      self.class._associations.dup.each do |association|
+        association_options = association.options
+
+        association_value = send(association.name)
 
-        serializer_class = ActiveModel::Serializer.serializer_for(association_value, association_options)
+        serializer_class = ActiveModel::Serializer.serializer_for(association_value, association.options)
 
         if serializer_class
           begin
             serializer = serializer_class.new(
               association_value,
-              options.except(:serializer).merge(serializer_from_options(association_options))
+              options.except(:serializer).merge(serializer_from_options(association.options))
             )
           rescue ActiveModel::Serializer::ArraySerializer::NoSerializerError
             virtual_value = association_value
             virtual_value = virtual_value.as_json if virtual_value.respond_to?(:as_json)
-            association_options[:association_options][:virtual_value] = virtual_value
+            association.options[:virtual_value] = virtual_value
           end
         elsif !association_value.nil? && !association_value.instance_of?(Object)
-          association_options[:association_options][:virtual_value] = association_value
+          association.options[:virtual_value] = association_value
         end
 
-        block.call(name, serializer, association_options[:association_options])
+        block.call(association.name, serializer, association.options)
       end
     end
 
diff --git a/test/adapter/json_api/has_many_explicit_serializer_test.rb b/test/adapter/json_api/has_many_explicit_serializer_test.rb
index 2adb0eb53..e7ac6e6ff 100644
--- a/test/adapter/json_api/has_many_explicit_serializer_test.rb
+++ b/test/adapter/json_api/has_many_explicit_serializer_test.rb
@@ -8,7 +8,7 @@ class JsonApi
         class HasManyExplicitSerializerTest < Minitest::Test
           def setup
             @post = Post.new(title: 'New Post', body: 'Body')
-            @author = Author.new(name: 'Jane Blogger')
+            @author = Author.new(name: 'Jane Blogger', roles: [], bio: nil)
             @author.posts = [@post]
             @post.author = @author
             @first_comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
@@ -58,9 +58,9 @@ def test_includes_linked_data
               },
               {
                 id: @author.id.to_s,
-                type: "authors",
+                type: 'authors',
                 relationships: {
-                  posts: { data: [ {type: "posts", id: @post.id.to_s } ] }
+                  posts: { data: [ {type: 'posts', id: @post.id.to_s } ] }
                 }
               }
             ]
diff --git a/test/serializers/associations_test.rb b/test/serializers/associations_test.rb
index 04681d2c4..dfc64dcee 100644
--- a/test/serializers/associations_test.rb
+++ b/test/serializers/associations_test.rb
@@ -39,26 +39,22 @@ def setup
         @post.author = @author
         @author.posts = [@post]
 
+        @post_serializer = PostSerializer.new(@post, {custom_options: true})
         @post_serializer = PostSerializer.new(@post, {custom_options: true})
         @author_serializer = AuthorSerializer.new(@author)
         @comment_serializer = CommentSerializer.new(@comment)
       end
 
       def test_has_many_and_has_one
-        assert_equal(
-          { posts: { type: :has_many, association_options: { embed: :ids } },
-            roles: { type: :has_many, association_options: { embed: :ids } },
-            bio: { type: :has_one, association_options: {} } },
-          @author_serializer.class._associations
-        )
         @author_serializer.each_association do |name, serializer, options|
-          if name == :posts
+          case name
+          when :posts
             assert_equal({embed: :ids}, options)
             assert_kind_of(ActiveModel::Serializer.config.array_serializer, serializer)
-          elsif name == :bio
+          when :bio
             assert_equal({}, options)
             assert_nil serializer
-          elsif name == :roles
+          when :roles
             assert_equal({embed: :ids}, options)
             assert_kind_of(ActiveModel::Serializer.config.array_serializer, serializer)
           else
@@ -84,16 +80,12 @@ def test_serializer_options_are_passed_into_associations_serializers
       end
 
       def test_belongs_to
-        assert_equal(
-          { post: { type: :belongs_to, association_options: {} },
-            author: { type: :belongs_to, association_options: {} } },
-          @comment_serializer.class._associations
-        )
         @comment_serializer.each_association do |name, serializer, options|
-          if name == :post
+          case name
+          when :post
             assert_equal({}, options)
             assert_kind_of(PostSerializer, serializer)
-          elsif name == :author
+          when :author
             assert_equal({}, options)
             assert_nil serializer
           else
@@ -122,15 +114,16 @@ def test_associations_inheritance_with_new_association
         inherited_klass = Class.new(PostSerializer) do
           has_many :top_comments, serializer: CommentSerializer
         end
-        expected_associations = PostSerializer._associations.merge(
-          top_comments: {
-            type: :has_many,
-            association_options: {
-              serializer: CommentSerializer
-            }
-          }
+
+        inherited_associations = inherited_klass._associations
+        parent_associations = PostSerializer._associations
+
+        assert(
+          parent_associations.all? do |association|
+            inherited_associations.include?(association)
+          end
         )
-        assert_equal(inherited_klass._associations, expected_associations)
+        assert(inherited_associations.map(&:name).include?(:top_comments))
       end
     end
   end