test case to illustrate current PostgreSQL composite behavior.

activerecord/test/cases/adapters/postgresql/composite_test.rb

+# -*- coding: utf-8 -*-
+require "cases/helper"
+require 'active_record/base'
+require 'active_record/connection_adapters/postgresql_adapter'
+
+class PostgresqlCompositeTest < ActiveRecord::TestCase
+  class PostgresqlComposite < ActiveRecord::Base
+    self.table_name = "postgresql_composites"
+  end
+
+  def teardown
+    @connection.execute 'DROP TABLE IF EXISTS postgresql_composites'
+    @connection.execute 'DROP TYPE IF EXISTS full_address'
+  end
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.transaction do
+      @connection.execute <<-SQL
+         CREATE TYPE full_address AS
+         (
+             city VARCHAR(90),
+             street VARCHAR(90)
+         );
+        SQL
+      @connection.create_table('postgresql_composites') do |t|
+        t.column :address, :full_address
+      end
+    end
+  end
+
+  def test_composite_mapping
+    @connection.execute "INSERT INTO postgresql_composites VALUES (1, ROW('Paris', 'Champs-Élysées'));"
+    composite = PostgresqlComposite.first
+    assert_equal "(Paris,Champs-Élysées)", composite.address
+
+    composite.address = "(Paris,Rue Basse)"
+    composite.save!
+
+    assert_equal '(Paris,"Rue Basse")', composite.reload.address
+  end
+end