1 files changed, 23 insertions, 9 deletions
diff --git a/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
index 4776e11128..5fca972aee 100644
--- a/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
+++ b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
@@ -8,6 +8,10 @@ module Namespaced
   class Post < ActiveRecord::Base
     self.table_name = "posts"
     has_one :tagging, as: :taggable, class_name: "Tagging"
+
+    def self.polymorphic_name
+      sti_name
+    end
   end
 end
 
@@ -25,34 +29,44 @@ module PolymorphicFullStiClassNamesSharedTest
   end
 
   def test_class_names
-    ActiveRecord::Base.store_full_sti_class = false
+    ActiveRecord::Base.store_full_sti_class = !store_full_sti_class
     post = Namespaced::Post.find_by_title("Great stuff")
-    assert_equal @tagging, post.tagging
+    assert_nil post.tagging
 
-    ActiveRecord::Base.store_full_sti_class = true
+    ActiveRecord::Base.store_full_sti_class = store_full_sti_class
     post = Namespaced::Post.find_by_title("Great stuff")
     assert_equal @tagging, post.tagging
   end
 
   def test_class_names_with_includes
-    ActiveRecord::Base.store_full_sti_class = false
+    ActiveRecord::Base.store_full_sti_class = !store_full_sti_class
     post = Namespaced::Post.includes(:tagging).find_by_title("Great stuff")
-    assert_equal @tagging, post.tagging
+    assert_nil post.tagging
 
-    ActiveRecord::Base.store_full_sti_class = true
+    ActiveRecord::Base.store_full_sti_class = store_full_sti_class
     post = Namespaced::Post.includes(:tagging).find_by_title("Great stuff")
     assert_equal @tagging, post.tagging
   end
 
   def test_class_names_with_eager_load
-    ActiveRecord::Base.store_full_sti_class = false
+    ActiveRecord::Base.store_full_sti_class = !store_full_sti_class
     post = Namespaced::Post.eager_load(:tagging).find_by_title("Great stuff")
-    assert_equal @tagging, post.tagging
+    assert_nil post.tagging
 
-    ActiveRecord::Base.store_full_sti_class = true
+    ActiveRecord::Base.store_full_sti_class = store_full_sti_class
     post = Namespaced::Post.eager_load(:tagging).find_by_title("Great stuff")
     assert_equal @tagging, post.tagging
   end
+
+  def test_class_names_with_find_by
+    post = Namespaced::Post.find_by_title("Great stuff")
+
+    ActiveRecord::Base.store_full_sti_class = !store_full_sti_class
+    assert_nil Tagging.find_by(taggable: post)
+
+    ActiveRecord::Base.store_full_sti_class = store_full_sti_class
+    assert_equal @tagging, Tagging.find_by(taggable: post)
+  end
 end
 
 class PolymorphicFullStiClassNamesTest < ActiveRecord::TestCase