Revert "Removing composed_of from ActiveRecord."

This reverts commit 14fc8b34521f8354a17e50cd11fa3f809e423592.

Reason: we need to discuss a better path from this removal.

Conflicts:
	activerecord/lib/active_record/reflection.rb
	activerecord/test/cases/base_test.rb
	activerecord/test/models/developer.rb

1 files changed, 24 insertions, 0 deletions

diff --git a/activerecord/test/cases/reflection_test.rb b/activerecord/test/cases/reflection_test.rb
index 51f07b6a2f..c803b93746 100644
--- a/activerecord/test/cases/reflection_test.rb
+++ b/activerecord/test/cases/reflection_test.rb
@@ -83,6 +83,30 @@ class ReflectionTest < ActiveRecord::TestCase
     end
   end
 
+  def test_aggregation_reflection
+    reflection_for_address = AggregateReflection.new(
+      :composed_of, :address, nil, { :mapping => [ %w(address_street street), %w(address_city city), %w(address_country country) ] }, Customer
+    )
+
+    reflection_for_balance = AggregateReflection.new(
+      :composed_of, :balance, nil, { :class_name => "Money", :mapping => %w(balance amount) }, Customer
+    )
+
+    reflection_for_gps_location = AggregateReflection.new(
+      :composed_of, :gps_location, nil, { }, Customer
+    )
+
+    assert Customer.reflect_on_all_aggregations.include?(reflection_for_gps_location)
+    assert Customer.reflect_on_all_aggregations.include?(reflection_for_balance)
+    assert Customer.reflect_on_all_aggregations.include?(reflection_for_address)
+
+    assert_equal reflection_for_address, Customer.reflect_on_aggregation(:address)
+
+    assert_equal Address, Customer.reflect_on_aggregation(:address).klass
+
+    assert_equal Money, Customer.reflect_on_aggregation(:balance).klass
+  end
+
   def test_reflect_on_all_autosave_associations
     expected = Pirate.reflect_on_all_associations.select { |r| r.options[:autosave] }
     received = Pirate.reflect_on_all_autosave_associations