Provide a slightly more robust we_can_set_the_inverse_on_this? method for polymorphic belongs_to associations. [#3520 state:resolved]

Also add a new test for polymorphic belongs_to that test direct accessor assignment, not just .replace assignment.

Signed-off-by: Eloy Duran <eloy.de.enige@gmail.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
index 2ab3aa141a..0696f06e5b 100644
--- a/activerecord/test/cases/associations/inverse_associations_test.rb
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -481,7 +481,22 @@ class InversePolymorphicBelongsToTests < ActiveRecord::TestCase
     assert_equal f.description, m.polymorphic_face.description, "Description of face should be the same after changes to parent-owned instance"
   end
 
-  def test_child_instance_should_be_shared_with_replaced_parent
+  def test_child_instance_should_be_shared_with_replaced_via_accessor_parent
+    face = faces(:confused)
+    old_man = face.polymorphic_man
+    new_man = Man.new
+
+    assert_not_nil face.polymorphic_man
+    face.polymorphic_man = new_man
+
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same before changes to parent instance"
+    face.description = 'Bongo'
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to parent instance"
+    new_man.polymorphic_face.description = 'Mungo'
+    assert_equal face.description, new_man.polymorphic_face.description, "Description of face should be the same after changes to replaced-parent-owned instance"
+  end
+
+  def test_child_instance_should_be_shared_with_replaced_via_method_parent
     face = faces(:confused)
     old_man = face.polymorphic_man
     new_man = Man.new