diff --git a/spec/polyamorous/join_association_spec.rb b/spec/polyamorous/join_association_spec.rb
index 8766f02..b07db29 100644
--- a/spec/polyamorous/join_association_spec.rb
+++ b/spec/polyamorous/join_association_spec.rb
@@ -10,6 +10,13 @@ module Polyamorous
       new_join_association(reflection, parent.children, Article)
     }
 
+    subject { new_join_association(reflection, parent.children, Person) }
+
+    it 'respects polymorphism on equality test' do
+      expect(subject).to eq new_join_association(reflection, parent.children, Person)
+      expect(subject).not_to eq new_join_association(reflection, parent.children, Article)
+    end
+
     it 'leaves the orginal reflection intact for thread safety' do
       reflection.instance_variable_set(:@klass, Article)
       join_association