Add tests for associations without counter_cache

Assert that counter_cache behaviour is not used on belongs_to or
has_many associations if the option is not given explicitly.

1 files changed, 21 insertions, 0 deletions

diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index 171cfbde44..328ea1061f 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -31,6 +31,8 @@ require 'models/student'
 require 'models/pirate'
 require 'models/ship'
 require 'models/ship_part'
+require 'models/treasure'
+require 'models/parrot'
 require 'models/tyre'
 require 'models/subscriber'
 require 'models/subscription'
@@ -932,6 +934,25 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 0, new_firm.clients_of_firm.size
   end
 
+  def test_has_many_without_counter_cache_option
+    # Ship has a conventionally named `treasures_count` column, but the counter_cache
+    # option is not given on the association.
+    ship = Ship.create(name: 'Countless', treasures_count: 10)
+
+    assert_not ship.treasures.instance_variable_get('@association').send(:has_cached_counter?)
+
+    # Count should come from sql count() of treasures rather than treasures_count attribute
+    assert_equal ship.treasures.size, 0
+
+    assert_no_difference lambda { ship.reload.treasures_count }, "treasures_count should not be changed" do
+      ship.treasures.create(name: 'Gold')
+    end
+
+    assert_no_difference lambda { ship.reload.treasures_count }, "treasures_count should not be changed" do
+      ship.treasures.destroy_all
+    end
+  end
+
   def test_deleting_updates_counter_cache
     topic = Topic.order("id ASC").first
     assert_equal topic.replies.to_a.size, topic.replies_count