Some basic tests for the :foreign_type option on belongs_to, which was...

Some basic tests for the :foreign_type option on belongs_to, which was previously completely untested.

activerecord/test/cases/associations/belongs_to_associations_test.rb

@@ -579,4 +579,23 @@ def test_polymorphic_counter_cache
       end
     end
   end
+
+  def test_polymorphic_with_custom_foreign_type
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    groucho = members(:groucho)
+    other   = members(:some_other_guy)
+
+    assert_equal groucho, sponsor.sponsorable
+    assert_equal groucho, sponsor.thing
+
+    sponsor.thing = other
+
+    assert_equal other, sponsor.sponsorable
+    assert_equal other, sponsor.thing
+
+    sponsor.sponsorable = groucho
+
+    assert_equal groucho, sponsor.sponsorable
+    assert_equal groucho, sponsor.thing
+  end
 end

activerecord/test/cases/associations/eager_test.rb

@@ -21,12 +21,13 @@
 require 'models/membership'
 require 'models/club'
 require 'models/categorization'
+require 'models/sponsor'
 
 class EagerAssociationTest < ActiveRecord::TestCase
   fixtures :posts, :comments, :authors, :author_addresses, :categories, :categories_posts,
             :companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,
             :owners, :pets, :author_favorites, :jobs, :references, :subscribers, :subscriptions, :books,
-            :developers, :projects, :developers_projects, :members, :memberships, :clubs
+            :developers, :projects, :developers_projects, :members, :memberships, :clubs, :sponsors
 
   def setup
     # preheat table existence caches
@@ -913,4 +914,14 @@ def test_preloading_has_many_through_with_uniq
     assert_equal 1, mary.unique_categorized_posts.length
     assert_equal 1, mary.unique_categorized_post_ids.length
   end
+
+  def test_preloading_polymorphic_with_custom_foreign_type
+    sponsor = sponsors(:moustache_club_sponsor_for_groucho)
+    groucho = members(:groucho)
+
+    sponsor = assert_queries(2) {
+      Sponsor.includes(:thing).where(:id => sponsor.id).first
+    }
+    assert_no_queries { assert_equal groucho, sponsor.thing }
+  end
 end

activerecord/test/models/sponsor.rb

 class Sponsor < ActiveRecord::Base
   belongs_to :sponsor_club, :class_name => "Club", :foreign_key => "club_id"
   belongs_to :sponsorable, :polymorphic => true
-end
\ No newline at end of file
+  belongs_to :thing, :polymorphic => true, :foreign_type => :sponsorable_type, :foreign_key => :sponsorable_id
+end