remove dynamic class creation where not needed (#1850)

* remove dynamic class creation where not needed

test/adapter/json/transform_test.rb

@@ -15,7 +15,7 @@ module ActiveModelSerializers
           @adapter = ActiveModelSerializers::Adapter::Json.new(serializer, options)
         end
 
-        Post = Class.new(::Model)
+        class Post < ::Model; end
         class PostSerializer < ActiveModel::Serializer
           attributes :id, :title, :body, :publish_at
         end

test/adapter/json_api/fields_test.rb

@@ -4,7 +4,10 @@ module ActiveModelSerializers
   module Adapter
     class JsonApi
       class FieldsTest < ActiveSupport::TestCase
-        Post = Class.new(::Model)
+        class Post < ::Model; end
+        class Author < ::Model; end
+        class Comment < ::Model; end
+
         class PostSerializer < ActiveModel::Serializer
           type 'posts'
           attributes :title, :body
@@ -12,13 +15,11 @@ module ActiveModelSerializers
           has_many :comments
         end
 
-        Author = Class.new(::Model)
         class AuthorSerializer < ActiveModel::Serializer
           type 'authors'
           attributes :name, :birthday
         end
 
-        Comment = Class.new(::Model)
         class CommentSerializer < ActiveModel::Serializer
           type 'comments'
           attributes :body

test/adapter/json_api/linked_test.rb

@@ -1,10 +1,9 @@
 require 'test_helper'
 
-NestedPost = Class.new(Model)
+class NestedPost < ::Model; end
 class NestedPostSerializer < ActiveModel::Serializer
   has_many :nested_posts
 end
-
 module ActiveModelSerializers
   module Adapter
     class JsonApi
@@ -283,8 +282,8 @@ module ActiveModelSerializers
       end
 
       class NoDuplicatesTest < ActiveSupport::TestCase
-        Post = Class.new(::Model)
-        Author = Class.new(::Model)
+        class Post < ::Model; end
+        class Author < ::Model; end
 
         class PostSerializer < ActiveModel::Serializer
           type 'posts'
@@ -303,8 +302,8 @@ module ActiveModelSerializers
           @author.posts << @post1
           @author.posts << @post2
 
-          @nestedpost1 = ::NestedPost.new(id: 1, nested_posts: [])
-          @nestedpost2 = ::NestedPost.new(id: 2, nested_posts: [])
+          @nestedpost1 = NestedPost.new(id: 1, nested_posts: [])
+          @nestedpost2 = NestedPost.new(id: 2, nested_posts: [])
           @nestedpost1.nested_posts << @nestedpost1
           @nestedpost1.nested_posts << @nestedpost2
           @nestedpost2.nested_posts << @nestedpost1

test/adapter/json_api/links_test.rb

@@ -4,7 +4,7 @@ module ActiveModelSerializers
   module Adapter
     class JsonApi
       class LinksTest < ActiveSupport::TestCase
-        LinkAuthor = Class.new(::Model)
+        class LinkAuthor < ::Model; end
         class LinkAuthorSerializer < ActiveModel::Serializer
           link :self do
             href "http://example.com/link_author/#{object.id}"

test/adapter/json_api/transform_test.rb

@@ -4,7 +4,10 @@ module ActiveModelSerializers
   module Adapter
     class JsonApi
       class KeyCaseTest < ActiveSupport::TestCase
-        Post = Class.new(::Model)
+        class Post < ::Model; end
+        class Author < ::Model; end
+        class Comment < ::Model; end
+
         class PostSerializer < ActiveModel::Serializer
           type 'posts'
           attributes :title, :body, :publish_at
@@ -23,13 +26,11 @@ module ActiveModelSerializers
           end
         end
 
-        Author = Class.new(::Model)
         class AuthorSerializer < ActiveModel::Serializer
           type 'authors'
           attributes :first_name, :last_name
         end
 
-        Comment = Class.new(::Model)
         class CommentSerializer < ActiveModel::Serializer
           type 'comments'
           attributes :body