1 files changed, 12 insertions, 0 deletions
diff --git a/activesupport/test/core_ext/class_test.rb b/activesupport/test/core_ext/class_test.rb
index a9c44907cc..9cc006fc63 100644
--- a/activesupport/test/core_ext/class_test.rb
+++ b/activesupport/test/core_ext/class_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "abstract_unit"
 require "active_support/core_ext/class"
 require "set"
@@ -25,4 +27,14 @@ class ClassTest < ActiveSupport::TestCase
     assert_equal [Baz], Bar.subclasses
     assert_equal [], Baz.subclasses
   end
+
+  def test_descendants_excludes_singleton_classes
+    klass = Parent.new.singleton_class
+    refute Parent.descendants.include?(klass), "descendants should not include singleton classes"
+  end
+
+  def test_subclasses_excludes_singleton_classes
+    klass = Parent.new.singleton_class
+    refute Parent.subclasses.include?(klass), "subclasses should not include singleton classes"
+  end
 end