A test for rails issue #14305

atest.rb

# Activate the gem you are reporting the issue against.
require 'active_record'
require 'minitest/autorun'
require 'logger'

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'postgresql', database: 'test')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do

  execute <<_SQL
  CREATE DOMAIN custom_money as numeric(8,2);
  CREATE TABLE postgresql_numeric_domains (
    id SERIAL PRIMARY KEY,
	amount numeric(8,2),
	custom_amount custom_money
  );
_SQL

end

class PostgresqlNumericDomain < ActiveRecord::Base
end

class BugTest < Minitest::Unit::TestCase

    def teardown
        [PostgresqlNumericDomain].each(&:delete_all)
    end
    
    # works, not using domain
    def test_numeric
      d = PostgresqlNumericDomain.create!(amount: '')
      assert_equal nil, d.amount
      assert_equal nil, d.custom_amount
    end

    # Currently fails, using domain
    def test_numeric_domain
      d = PostgresqlNumericDomain.create!(custom_amount: '')
      assert_equal nil, d.amount
      assert_equal nil, d.custom_amount
    end

end