From ab6bd600e30becf1eef5f6ad64cb0e40d7e93798 Mon Sep 17 00:00:00 2001
From: kevintyll <kevintyll@gmail.com>
Date: Wed, 25 Nov 2015 12:31:32 -0500
Subject: [PATCH 1/2] When caching, return the object's cache_key up front if
 it's defined.

This will prevent objects PORO objects that don't have updated_at defined, from throwing an error.

Not as big a deal now that PORO objects can inherit ActiveModelSerializers::Model, but still necessary if it's not inherited for whatever reason.

Add the Adapter type to the cache key.

This prevents incorrect results when the same object is serialized with different adapters.

BF:

Cherry-pick of
https://github.com/bf4/active_model_serializers/commit/040a97b9e9005ee6cb55f5a3d9088098407f54c2
which was a squash of
https://github.com/rails-api/active_model_serializers/commits/f89ed71058322fe7dd35d5c8b209856f8e03ad14

from pr 1346
---
 lib/active_model/serializer/caching.rb        | 18 ++++-
 lib/active_model_serializers/adapter/base.rb  |  8 +++
 .../cached_serializer.rb                      | 20 +++---
 test/cache_test.rb                            | 69 +++++++++++++++----
 test/fixtures/poro.rb                         |  4 +-
 5 files changed, 91 insertions(+), 28 deletions(-)

diff --git a/lib/active_model/serializer/caching.rb b/lib/active_model/serializer/caching.rb
index 85a395d3..d1db9a3d 100644
--- a/lib/active_model/serializer/caching.rb
+++ b/lib/active_model/serializer/caching.rb
@@ -7,7 +7,7 @@ module ActiveModel
         with_options instance_writer: false, instance_reader: false do |serializer|
           serializer.class_attribute :_cache         # @api private : the cache store
           serializer.class_attribute :_fragmented    # @api private : @see ::fragmented
-          serializer.class_attribute :_cache_key     # @api private : when present, is first item in cache_key
+          serializer.class_attribute :_cache_key     # @api private : when present, is first item in cache_key.  Ignored if the serializable object defines #cache_key.
           serializer.class_attribute :_cache_only    # @api private : when fragment caching, whitelists cached_attributes. Cannot combine with except
           serializer.class_attribute :_cache_except  # @api private : when fragment caching, blacklists cached_attributes. Cannot combine with only
           serializer.class_attribute :_cache_options # @api private : used by CachedSerializer, passed to _cache.fetch
@@ -58,6 +58,10 @@ module ActiveModel
           ''.freeze
         end
 
+        def _skip_digest?
+          _cache_options && _cache_options[:skip_digest]
+        end
+
         # @api private
         # Used by FragmentCache on the CachedSerializer
         #  to call attribute methods on the fragmented cached serializer.
@@ -142,6 +146,18 @@ module ActiveModel
             (_cache_only && !_cache_except || !_cache_only && _cache_except)
         end
       end
+
+      # Use object's cache_key if available, else derive a key from the object
+      # Pass the `key` option to the `cache` declaration or override this method to customize the cache key
+      def cache_key
+        if object.respond_to?(:cache_key)
+          object.cache_key
+        else
+          object_time_safe = object.updated_at
+          object_time_safe = object_time_safe.strftime('%Y%m%d%H%M%S%9N') if object_time_safe.respond_to?(:strftime)
+          "#{self.class._cache_key}/#{object.id}-#{object_time_safe}"
+        end
+      end
     end
   end
 end
diff --git a/lib/active_model_serializers/adapter/base.rb b/lib/active_model_serializers/adapter/base.rb
index cc6092d6..9fa62edc 100644
--- a/lib/active_model_serializers/adapter/base.rb
+++ b/lib/active_model_serializers/adapter/base.rb
@@ -8,6 +8,10 @@ module ActiveModelSerializers
         ActiveModelSerializers::Adapter.register(subclass)
       end
 
+      def self.name
+        to_s.demodulize
+      end
+
       attr_reader :serializer, :instance_options
 
       def initialize(serializer, options = {})
@@ -15,6 +19,10 @@ module ActiveModelSerializers
         @instance_options = options
       end
 
+      def name
+        self.class.name
+      end
+
       def serializable_hash(_options = nil)
         fail NotImplementedError, 'This is an abstract method. Should be implemented at the concrete adapter.'
       end
diff --git a/lib/active_model_serializers/cached_serializer.rb b/lib/active_model_serializers/cached_serializer.rb
index 11a6259d..117ff0d8 100644
--- a/lib/active_model_serializers/cached_serializer.rb
+++ b/lib/active_model_serializers/cached_serializer.rb
@@ -1,13 +1,16 @@
 module ActiveModelSerializers
   class CachedSerializer
+    UndefinedCacheKey = Class.new(StandardError)
+
     def initialize(serializer)
       @cached_serializer = serializer
-      @klass             = @cached_serializer.class
+      return unless cached? && !@cached_serializer.object.respond_to?(:cache_key) && @klass._cache_key.blank?
+      fail(UndefinedCacheKey, "#{@cached_serializer.object} must define #cache_key, or the cache_key option must be passed into cache on #{@cached_serializer}")
     end
 
     def cache_check(adapter_instance)
       if cached?
-        @klass._cache.fetch(cache_key, @klass._cache_options) do
+        @klass._cache.fetch(cache_key(adapter_instance), @klass._cache_options) do
           yield
         end
       elsif fragment_cached?
@@ -25,21 +28,16 @@ module ActiveModelSerializers
       @klass.fragment_cache_enabled?
     end
 
-    def cache_key
+    def cache_key(adapter_instance)
       return @cache_key if defined?(@cache_key)
 
       parts = []
-      parts << object_cache_key
-      parts << @klass._cache_digest unless @klass._cache_options && @klass._cache_options[:skip_digest]
+      parts << @cached_serializer.cache_key
+      parts << adapter_instance.name.underscore
+      parts << @klass._cache_digest unless @klass._skip_digest?
       @cache_key = parts.join('/')
     end
 
-    def object_cache_key
-      object_time_safe = @cached_serializer.object.updated_at
-      object_time_safe = object_time_safe.strftime('%Y%m%d%H%M%S%9N') if object_time_safe.respond_to?(:strftime)
-      @klass._cache_key ? "#{@klass._cache_key}/#{@cached_serializer.object.id}-#{object_time_safe}" : @cached_serializer.object.cache_key
-    end
-
     # find all cache_key for the collection_serializer
     # @param collection_serializer
     # @param include_tree
diff --git a/test/cache_test.rb b/test/cache_test.rb
index d4c9fb72..f30d0284 100644
--- a/test/cache_test.rb
+++ b/test/cache_test.rb
@@ -4,6 +4,21 @@ require 'tempfile'
 
 module ActiveModelSerializers
   class CacheTest < ActiveSupport::TestCase
+    UncachedAuthor = Class.new(Author) do
+      # To confirm cache_key is set using updated_at and cache_key option passed to cache
+      undef_method :cache_key
+    end
+
+    Article = Class.new(::Model) do
+      # To confirm error is raised when cache_key is not set and cache_key option not passed to cache
+      undef_method :cache_key
+    end
+
+    ArticleSerializer = Class.new(ActiveModel::Serializer) do
+      cache only: [:place], skip_digest: true
+      attributes :title
+    end
+
     InheritedRoleSerializer = Class.new(RoleSerializer) do
       cache key: 'inherited_role', only: [:name, :special_attribute]
       attribute :special_attribute
@@ -81,15 +96,26 @@ module ActiveModelSerializers
       assert_equal(nil, @comment_serializer.class._cache_key)
     end
 
-    def test_cache_key_interpolation_with_updated_at
-      render_object_with_cache(@author)
-      assert_equal(nil, cache_store.fetch(@author.cache_key))
-      assert_equal(@author_serializer.attributes.to_json, cache_store.fetch("#{@author_serializer.class._cache_key}/#{@author_serializer.object.id}-#{@author_serializer.object.updated_at.strftime("%Y%m%d%H%M%S%9N")}").to_json)
+
+    def test_error_is_raised_if_cache_key_is_not_defined_on_object_or_passed_as_cache_option
+      article = Article.new(title: 'Must Read')
+      assert_raises ActiveModel::Serializer::Adapter::CachedSerializer::UndefinedCacheKey do
+        render_object_with_cache(article)
+      end
+    end
+
+    def test_cache_key_interpolation_with_updated_at_when_cache_key_is_not_defined_on_object
+      uncached_author            = UncachedAuthor.new(name: 'Joao M. D. Moura')
+      uncached_author_serializer = AuthorSerializer.new(uncached_author)
+
+      render_object_with_cache(uncached_author)
+      key = cache_key_with_adapter("#{uncached_author_serializer.class._cache_key}/#{uncached_author_serializer.object.id}-#{uncached_author_serializer.object.updated_at.strftime("%Y%m%d%H%M%S%9N")}")
+      assert_equal(uncached_author_serializer.attributes.to_json, ActionController::Base.cache_store.fetch(key).to_json)
     end
 
     def test_default_cache_key_fallback
       render_object_with_cache(@comment)
-      assert_equal(@comment_serializer.attributes.to_json, cache_store.fetch(@comment.cache_key).to_json)
+      assert_equal(@comment_serializer.attributes.to_json, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)).to_json)
     end
 
     def test_cache_options_definition
@@ -111,8 +137,8 @@ module ActiveModelSerializers
       Timecop.freeze(Time.current) do
         render_object_with_cache(@post)
 
-        assert_equal(@post_serializer.attributes, cache_store.fetch(@post.cache_key))
-        assert_equal(@comment_serializer.attributes, cache_store.fetch(@comment.cache_key))
+        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
+        assert_equal(@comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)))
       end
     end
 
@@ -122,8 +148,9 @@ module ActiveModelSerializers
         render_object_with_cache(@post)
 
         # Check if it cached the objects separately
-        assert_equal(@post_serializer.attributes,    cached_serialization(@post_serializer))
-        assert_equal(@comment_serializer.attributes, cached_serialization(@comment_serializer))
+        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
+        assert_equal(@comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)))
+
 
         # Simulating update on comments relationship with Post
         new_comment            = Comment.new(id: 2567, body: 'ZOMG A NEW COMMENT')
@@ -134,8 +161,8 @@ module ActiveModelSerializers
         render_object_with_cache(@post)
 
         # Check if the the new comment was cached
-        assert_equal(new_comment_serializer.attributes, cached_serialization(new_comment_serializer))
-        assert_equal(@post_serializer.attributes, cached_serialization(@post_serializer))
+        assert_equal(new_comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(new_comment.cache_key)))
+        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
       end
     end
 
@@ -150,7 +177,7 @@ module ActiveModelSerializers
       hash = render_object_with_cache(@location)
 
       assert_equal(hash, expected_result)
-      assert_equal({ place: 'Nowhere' }, cache_store.fetch(@location.cache_key))
+      assert_equal({ place: 'Nowhere' }, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@location.cache_key)))
     end
 
     def test_fragment_cache_with_inheritance
@@ -161,9 +188,14 @@ module ActiveModelSerializers
       refute_includes(base.keys, :special_attribute)
     end
 
+    def test_uses_adapter_in_cache_key
+      render_object_with_cache(@post)
+      assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch("#{@post.cache_key}/#{adapter.class.to_s.demodulize.underscore}"))
+    end
+
     def test_uses_file_digest_in_cache_key
       render_object_with_cache(@blog)
-      assert_equal(@blog_serializer.attributes, cache_store.fetch(@blog.cache_key_with_digest))
+      assert_equal(@blog_serializer.attributes, ActionController::Base.cache_store.fetch("#{cache_key_with_adapter(@blog.cache_key)}/#{@blog.class::FILE_DIGEST}"))
     end
 
     def test_cache_digest_definition
@@ -254,7 +286,16 @@ module ActiveModelSerializers
     private
 
     def render_object_with_cache(obj, options = {})
-      serializable(obj, options).serializable_hash
+      @serializable_resource = serializable(obj, options).serializable_hash
+      @serializable_resource.serializable_hash
+    end
+
+    def adapter
+      @serializable_resource.adapter
+    end
+
+    def cache_key_with_adapter(key)
+      "#{key}/#{adapter.name.underscore}"
     end
 
     def cache_store
diff --git a/test/fixtures/poro.rb b/test/fixtures/poro.rb
index b1351364..c2bddf8e 100644
--- a/test/fixtures/poro.rb
+++ b/test/fixtures/poro.rb
@@ -55,8 +55,8 @@ Bio      = Class.new(Model)
 Blog     = Class.new(Model) do
   FILE_DIGEST = Digest::MD5.hexdigest(File.open(__FILE__).read)
 
-  def cache_key_with_digest
-    "#{cache_key}/#{FILE_DIGEST}"
+  def digest
+    FILE_DIGEST
   end
 end
 Role     = Class.new(Model)

From 4ba4c298ec204bcf2625e630a3e9eefede03e3ef Mon Sep 17 00:00:00 2001
From: Benjamin Fleischer <github@benjaminfleischer.com>
Date: Thu, 31 Mar 2016 13:57:38 -0500
Subject: [PATCH 2/2] Prefer object.cache_key when available.

---
 CHANGELOG.md                                  |  2 +
 lib/active_model/serializer/caching.rb        | 16 -----
 lib/active_model_serializers/adapter/base.rb  |  8 ---
 .../cached_serializer.rb                      | 26 +++++--
 test/cache_test.rb                            | 69 +++++++++----------
 test/fixtures/poro.rb                         | 10 +--
 6 files changed, 55 insertions(+), 76 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 03daa367..8340262f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@
 Breaking changes:
 
 Features:
+- [#1642](https://github.com/rails-api/active_model_serializers/pull/1642) Prefer object.cache_key over the generated
+  cache key. (@bf4 via #1346 by @kevintyll)
 - [#1637](https://github.com/rails-api/active_model_serializers/pull/1637) Make references to 'ActionController::Base.cache_store' explicit
   in order to avoid issues when application controllers inherit from 'ActionController::API'. (@ncuesta)
 - [#1633](https://github.com/rails-api/active_model_serializers/pull/1633) Yield 'serializer' to serializer association blocks. (@bf4)
diff --git a/lib/active_model/serializer/caching.rb b/lib/active_model/serializer/caching.rb
index d1db9a3d..0d2160af 100644
--- a/lib/active_model/serializer/caching.rb
+++ b/lib/active_model/serializer/caching.rb
@@ -58,10 +58,6 @@ module ActiveModel
           ''.freeze
         end
 
-        def _skip_digest?
-          _cache_options && _cache_options[:skip_digest]
-        end
-
         # @api private
         # Used by FragmentCache on the CachedSerializer
         #  to call attribute methods on the fragmented cached serializer.
@@ -146,18 +142,6 @@ module ActiveModel
             (_cache_only && !_cache_except || !_cache_only && _cache_except)
         end
       end
-
-      # Use object's cache_key if available, else derive a key from the object
-      # Pass the `key` option to the `cache` declaration or override this method to customize the cache key
-      def cache_key
-        if object.respond_to?(:cache_key)
-          object.cache_key
-        else
-          object_time_safe = object.updated_at
-          object_time_safe = object_time_safe.strftime('%Y%m%d%H%M%S%9N') if object_time_safe.respond_to?(:strftime)
-          "#{self.class._cache_key}/#{object.id}-#{object_time_safe}"
-        end
-      end
     end
   end
 end
diff --git a/lib/active_model_serializers/adapter/base.rb b/lib/active_model_serializers/adapter/base.rb
index 9fa62edc..cc6092d6 100644
--- a/lib/active_model_serializers/adapter/base.rb
+++ b/lib/active_model_serializers/adapter/base.rb
@@ -8,10 +8,6 @@ module ActiveModelSerializers
         ActiveModelSerializers::Adapter.register(subclass)
       end
 
-      def self.name
-        to_s.demodulize
-      end
-
       attr_reader :serializer, :instance_options
 
       def initialize(serializer, options = {})
@@ -19,10 +15,6 @@ module ActiveModelSerializers
         @instance_options = options
       end
 
-      def name
-        self.class.name
-      end
-
       def serializable_hash(_options = nil)
         fail NotImplementedError, 'This is an abstract method. Should be implemented at the concrete adapter.'
       end
diff --git a/lib/active_model_serializers/cached_serializer.rb b/lib/active_model_serializers/cached_serializer.rb
index 117ff0d8..9eea3967 100644
--- a/lib/active_model_serializers/cached_serializer.rb
+++ b/lib/active_model_serializers/cached_serializer.rb
@@ -4,13 +4,12 @@ module ActiveModelSerializers
 
     def initialize(serializer)
       @cached_serializer = serializer
-      return unless cached? && !@cached_serializer.object.respond_to?(:cache_key) && @klass._cache_key.blank?
-      fail(UndefinedCacheKey, "#{@cached_serializer.object} must define #cache_key, or the cache_key option must be passed into cache on #{@cached_serializer}")
+      @klass             = @cached_serializer.class
     end
 
     def cache_check(adapter_instance)
       if cached?
-        @klass._cache.fetch(cache_key(adapter_instance), @klass._cache_options) do
+        @klass._cache.fetch(cache_key, @klass._cache_options) do
           yield
         end
       elsif fragment_cached?
@@ -28,16 +27,29 @@ module ActiveModelSerializers
       @klass.fragment_cache_enabled?
     end
 
-    def cache_key(adapter_instance)
+    def cache_key
       return @cache_key if defined?(@cache_key)
 
       parts = []
-      parts << @cached_serializer.cache_key
-      parts << adapter_instance.name.underscore
-      parts << @klass._cache_digest unless @klass._skip_digest?
+      parts << object_cache_key
+      parts << @klass._cache_digest unless @klass._cache_options && @klass._cache_options[:skip_digest]
       @cache_key = parts.join('/')
     end
 
+    # Use object's cache_key if available, else derive a key from the object
+    # Pass the `key` option to the `cache` declaration or override this method to customize the cache key
+    def object_cache_key
+      if @cached_serializer.object.respond_to?(:cache_key)
+        @cached_serializer.object.cache_key
+      elsif (cache_key = (@klass._cache_key || @klass._cache_options[:key]))
+        object_time_safe = @cached_serializer.object.updated_at
+        object_time_safe = object_time_safe.strftime('%Y%m%d%H%M%S%9N') if object_time_safe.respond_to?(:strftime)
+        "#{cache_key}/#{@cached_serializer.object.id}-#{object_time_safe}"
+      else
+        fail UndefinedCacheKey, "#{@cached_serializer.object.class} must define #cache_key, or the 'key:' option must be passed into '#{@klass}.cache'"
+      end
+    end
+
     # find all cache_key for the collection_serializer
     # @param collection_serializer
     # @param include_tree
diff --git a/test/cache_test.rb b/test/cache_test.rb
index f30d0284..d5049656 100644
--- a/test/cache_test.rb
+++ b/test/cache_test.rb
@@ -96,26 +96,27 @@ module ActiveModelSerializers
       assert_equal(nil, @comment_serializer.class._cache_key)
     end
 
-
-    def test_error_is_raised_if_cache_key_is_not_defined_on_object_or_passed_as_cache_option
-      article = Article.new(title: 'Must Read')
-      assert_raises ActiveModel::Serializer::Adapter::CachedSerializer::UndefinedCacheKey do
-        render_object_with_cache(article)
-      end
-    end
-
     def test_cache_key_interpolation_with_updated_at_when_cache_key_is_not_defined_on_object
       uncached_author            = UncachedAuthor.new(name: 'Joao M. D. Moura')
       uncached_author_serializer = AuthorSerializer.new(uncached_author)
 
       render_object_with_cache(uncached_author)
-      key = cache_key_with_adapter("#{uncached_author_serializer.class._cache_key}/#{uncached_author_serializer.object.id}-#{uncached_author_serializer.object.updated_at.strftime("%Y%m%d%H%M%S%9N")}")
-      assert_equal(uncached_author_serializer.attributes.to_json, ActionController::Base.cache_store.fetch(key).to_json)
+      key = "#{uncached_author_serializer.class._cache_key}/#{uncached_author_serializer.object.id}-#{uncached_author_serializer.object.updated_at.strftime("%Y%m%d%H%M%S%9N")}"
+      assert_equal(uncached_author_serializer.attributes.to_json, cache_store.fetch(key).to_json)
     end
 
     def test_default_cache_key_fallback
       render_object_with_cache(@comment)
-      assert_equal(@comment_serializer.attributes.to_json, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)).to_json)
+      key = @comment.cache_key
+      assert_equal(@comment_serializer.attributes.to_json, cache_store.fetch(key).to_json)
+    end
+
+    def test_error_is_raised_if_cache_key_is_not_defined_on_object_or_passed_as_cache_option
+      article = Article.new(title: 'Must Read')
+      e = assert_raises ActiveModelSerializers::CachedSerializer::UndefinedCacheKey do
+        render_object_with_cache(article)
+      end
+      assert_match(/ActiveModelSerializers::CacheTest::Article must define #cache_key, or the 'key:' option must be passed into 'CachedActiveModelSerializers_CacheTest_ArticleSerializer.cache'/, e.message)
     end
 
     def test_cache_options_definition
@@ -137,8 +138,10 @@ module ActiveModelSerializers
       Timecop.freeze(Time.current) do
         render_object_with_cache(@post)
 
-        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
-        assert_equal(@comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)))
+        key = @post.cache_key
+        assert_equal(@post_serializer.attributes, cache_store.fetch(key))
+        key = @comment.cache_key
+        assert_equal(@comment_serializer.attributes, cache_store.fetch(key))
       end
     end
 
@@ -148,9 +151,10 @@ module ActiveModelSerializers
         render_object_with_cache(@post)
 
         # Check if it cached the objects separately
-        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
-        assert_equal(@comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)))
-
+        key = @post.cache_key
+        assert_equal(@post_serializer.attributes, cache_store.fetch(key))
+        key = @comment.cache_key
+        assert_equal(@comment_serializer.attributes, cache_store.fetch(key))
 
         # Simulating update on comments relationship with Post
         new_comment            = Comment.new(id: 2567, body: 'ZOMG A NEW COMMENT')
@@ -161,8 +165,10 @@ module ActiveModelSerializers
         render_object_with_cache(@post)
 
         # Check if the the new comment was cached
-        assert_equal(new_comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(new_comment.cache_key)))
-        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
+        key = new_comment.cache_key
+        assert_equal(new_comment_serializer.attributes, cache_store.fetch(key))
+        key = @post.cache_key
+        assert_equal(@post_serializer.attributes, cache_store.fetch(key))
       end
     end
 
@@ -177,7 +183,7 @@ module ActiveModelSerializers
       hash = render_object_with_cache(@location)
 
       assert_equal(hash, expected_result)
-      assert_equal({ place: 'Nowhere' }, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@location.cache_key)))
+      assert_equal({ place: 'Nowhere' }, cache_store.fetch(@location.cache_key))
     end
 
     def test_fragment_cache_with_inheritance
@@ -188,18 +194,14 @@ module ActiveModelSerializers
       refute_includes(base.keys, :special_attribute)
     end
 
-    def test_uses_adapter_in_cache_key
-      render_object_with_cache(@post)
-      assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch("#{@post.cache_key}/#{adapter.class.to_s.demodulize.underscore}"))
-    end
-
     def test_uses_file_digest_in_cache_key
       render_object_with_cache(@blog)
-      assert_equal(@blog_serializer.attributes, ActionController::Base.cache_store.fetch("#{cache_key_with_adapter(@blog.cache_key)}/#{@blog.class::FILE_DIGEST}"))
+      key = "#{@blog.cache_key}/#{::Model::FILE_DIGEST}"
+      assert_equal(@blog_serializer.attributes, cache_store.fetch(key))
     end
 
     def test_cache_digest_definition
-      assert_equal(FILE_DIGEST, @post_serializer.class._cache_digest)
+      assert_equal(::Model::FILE_DIGEST, @post_serializer.class._cache_digest)
     end
 
     def test_object_cache_keys
@@ -211,7 +213,7 @@ module ActiveModelSerializers
       assert_equal actual.size, 3
       assert actual.any? { |key| key == 'comment/1' }
       assert actual.any? { |key| key =~ %r{post/post-\d+} }
-      assert actual.any? { |key| key =~ %r{writer/author-\d+} }
+      assert actual.any? { |key| key =~ %r{author/author-\d+} }
     end
 
     def test_cached_attributes
@@ -228,7 +230,7 @@ module ActiveModelSerializers
         assert_equal cached_attributes[@comment.post.cache_key], Post.new(id: 'post', title: 'New Post', body: 'Body').attributes
 
         writer = @comment.post.blog.writer
-        writer_cache_key = "writer/#{writer.id}-#{writer.updated_at.strftime("%Y%m%d%H%M%S%9N")}"
+        writer_cache_key = writer.cache_key
 
         assert_equal cached_attributes[writer_cache_key], Author.new(id: 'author', name: 'Joao M. D. Moura').attributes
       end
@@ -286,16 +288,7 @@ module ActiveModelSerializers
     private
 
     def render_object_with_cache(obj, options = {})
-      @serializable_resource = serializable(obj, options).serializable_hash
-      @serializable_resource.serializable_hash
-    end
-
-    def adapter
-      @serializable_resource.adapter
-    end
-
-    def cache_key_with_adapter(key)
-      "#{key}/#{adapter.name.underscore}"
+      serializable(obj, options).serializable_hash
     end
 
     def cache_store
diff --git a/test/fixtures/poro.rb b/test/fixtures/poro.rb
index c2bddf8e..9689e615 100644
--- a/test/fixtures/poro.rb
+++ b/test/fixtures/poro.rb
@@ -1,6 +1,8 @@
 verbose = $VERBOSE
 $VERBOSE = nil
 class Model < ActiveModelSerializers::Model
+  FILE_DIGEST = Digest::MD5.hexdigest(File.open(__FILE__).read)
+
   ### Helper methods, not required to be serializable
 
   # Convenience when not adding @attributes readers and writers
@@ -52,13 +54,7 @@ Post     = Class.new(Model)
 Like     = Class.new(Model)
 Author   = Class.new(Model)
 Bio      = Class.new(Model)
-Blog     = Class.new(Model) do
-  FILE_DIGEST = Digest::MD5.hexdigest(File.open(__FILE__).read)
-
-  def digest
-    FILE_DIGEST
-  end
-end
+Blog     = Class.new(Model)
 Role     = Class.new(Model)
 User     = Class.new(Model)
 Location = Class.new(Model)