test, show current adapter behavior for `add_column limit: nil`.

This is an illustration of https://github.com/rails/rails/pull/13435#issuecomment-33789752
Removing the limit from the PG and SQLite adapter solves the issue.
MySQL is still affected by the issue.

1 files changed, 8 insertions, 0 deletions

diff --git a/activerecord/test/cases/migration/column_attributes_test.rb b/activerecord/test/cases/migration/column_attributes_test.rb
index ccf19fb4d0..6a02873cba 100644
--- a/activerecord/test/cases/migration/column_attributes_test.rb
+++ b/activerecord/test/cases/migration/column_attributes_test.rb
@@ -35,6 +35,14 @@ module ActiveRecord
         assert_no_column TestModel, :last_name
       end
 
+      def test_add_column_without_limit
+        # TODO: limit: nil should work with all adapters.
+        skip "MySQL wrongly enforces a limit of 255" if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
+        add_column :test_models, :description, :string, limit: nil
+        TestModel.reset_column_information
+        assert_nil TestModel.columns_hash["description"].limit
+      end
+
       if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
         def test_unabstracted_database_dependent_types
           add_column :test_models, :intelligence_quotient, :tinyint