Use instance_accessor: false instead of instance_writer.

3 files changed, 11 insertions, 7 deletions

diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 04b1d75e3e..63981a68a9 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -604,6 +604,12 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal "changed", post.body
   end
 
+  def test_attr_readonly_is_class_level_setting
+    post = ReadonlyTitlePost.new
+    assert_raise(NoMethodError) { post._attr_readonly = [:title] }
+    assert_deprecated { post._attr_readonly }
+  end
+
   def test_non_valid_identifier_column_name
     weird = Weird.create('a$b' => 'value')
     weird.reload
diff --git a/activerecord/test/cases/serialization_test.rb b/activerecord/test/cases/serialization_test.rb
index ce167509c1..10d8ccc711 100644
--- a/activerecord/test/cases/serialization_test.rb
+++ b/activerecord/test/cases/serialization_test.rb
@@ -53,9 +53,8 @@ class SerializationTest < ActiveRecord::TestCase
   end
 
   def test_serialized_attributes_are_class_level_settings
-    assert_raise NoMethodError do
-      topic = Topic.new
-      topic.serialized_attributes = []
-    end
+    topic = Topic.new
+    assert_raise(NoMethodError) { topic.serialized_attributes = [] }
+    assert_deprecated { topic.serialized_attributes }
   end
 end
diff --git a/activerecord/test/cases/store_test.rb b/activerecord/test/cases/store_test.rb
index 3e60b62fd5..fb0d116c08 100644
--- a/activerecord/test/cases/store_test.rb
+++ b/activerecord/test/cases/store_test.rb
@@ -122,9 +122,8 @@ class StoreTest < ActiveRecord::TestCase
   end
 
   test "stores_attributes are class level settings" do
-    assert_raise NoMethodError do
-      @john.stored_attributes = {}
-    end
+    assert_raise(NoMethodError) { @john.stored_attributes = Hash.new }
+    assert_raise(NoMethodError) { @john.stored_attributes }
   end
 
 end