1 files changed, 44 insertions, 0 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
new file mode 100644
index 0000000000..8754889143
--- /dev/null
+++ b/activerecord/test/cases/associations/eager_load_includes_full_sti_class_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "models/tagging"
+
+module Namespaced
+  class Post < ActiveRecord::Base
+    self.table_name = "posts"
+    has_one :tagging, as: :taggable, class_name: "Tagging"
+  end
+end
+
+class EagerLoadIncludeFullStiClassNamesTest < ActiveRecord::TestCase
+  def setup
+    post = Namespaced::Post.create(title: "Great stuff", body: "This is not", author_id: 1)
+    @tagging = Tagging.create(taggable: post)
+    @old = ActiveRecord::Base.store_full_sti_class
+  end
+
+  def teardown
+    ActiveRecord::Base.store_full_sti_class = @old
+  end
+
+  def test_class_names_with_includes
+    ActiveRecord::Base.store_full_sti_class = false
+    post = Namespaced::Post.includes(:tagging).find_by_title("Great stuff")
+    assert_nil post.tagging
+
+    ActiveRecord::Base.store_full_sti_class = true
+    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
+    post = Namespaced::Post.eager_load(:tagging).find_by_title("Great stuff")
+    assert_nil post.tagging
+
+    ActiveRecord::Base.store_full_sti_class = true
+    post = Namespaced::Post.eager_load(:tagging).find_by_title("Great stuff")
+    assert_equal @tagging, post.tagging
+  end
+end