diff --git a/activerecord/test/cases/adapters/postgresql/json_test.rb b/activerecord/test/cases/adapters/postgresql/json_test.rb
index 79dcfe110c..ee08841eb3 100644
--- a/activerecord/test/cases/adapters/postgresql/json_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/json_test.rb
@@ -21,8 +21,8 @@ module PostgresqlJSONSharedTestCases
     @connection.add_column "json_data_type", "permissions", column_type, default: { "users": "read", "posts": ["read", "write"] }
     klass.reset_column_information
 
-    assert_equal({ "users" => "read", "posts" => ["read", "write"] }, JsonDataType.column_defaults["permissions"])
-    assert_equal({ "users" => "read", "posts" => ["read", "write"] }, JsonDataType.new.permissions)
+    assert_equal({ "users" => "read", "posts" => ["read", "write"] }, klass.column_defaults["permissions"])
+    assert_equal({ "users" => "read", "posts" => ["read", "write"] }, klass.new.permissions)
   end
 
   def test_deserialize_with_array
@@ -33,15 +33,6 @@ module PostgresqlJSONSharedTestCases
     x.reload
     assert_equal ["foo" => "bar"], x.objects
   end
-
-  def test_not_compatible_with_serialize_macro
-    new_klass = Class.new(klass) do
-      serialize :payload, JSON
-    end
-    assert_raises(ActiveRecord::AttributeMethods::Serialization::ColumnNotSerializableError) do
-      new_klass.new
-    end
-  end
 end
 
 class PostgresqlJSONTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/json_shared_test_cases.rb b/activerecord/test/cases/json_shared_test_cases.rb
index f708acf0aa..952194c6dc 100644
--- a/activerecord/test/cases/json_shared_test_cases.rb
+++ b/activerecord/test/cases/json_shared_test_cases.rb
@@ -216,6 +216,15 @@ module JSONSharedTestCases
     assert_equal true, json.payload
   end
 
+  def test_not_compatible_with_serialize_macro
+    new_klass = Class.new(klass) do
+      serialize :payload, JSON
+    end
+    assert_raises(ActiveRecord::AttributeMethods::Serialization::ColumnNotSerializableError) do
+      new_klass.new
+    end
+  end
+
   private
     def klass
       JsonDataType