2 files changed, 82 insertions, 1 deletions
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
index 6b4f826766..a85b56ac4b 100644
--- a/activerecord/test/cases/associations/belongs_to_associations_test.rb
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -37,6 +37,13 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal companies(:first_firm).name, firm.name
   end
 
+  def test_assigning_belongs_to_on_destroyed_object
+    client = Client.create!(name: "Client")
+    client.destroy!
+    assert_raise(frozen_error_class) { client.firm = nil }
+    assert_raise(frozen_error_class) { client.firm = Firm.new(name: "Firm") }
+  end
+
   def test_missing_attribute_error_is_raised_when_no_foreign_key_attribute
     assert_raises(ActiveModel::MissingAttributeError) { Client.select(:id).first.firm }
   end
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index 33fe5ccabc..2e0a7ab1ab 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -989,10 +989,20 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 0, post.readers.size
     post.readers.reset
     post.readers.build
-    assert_equal [], post.reader_ids
+    assert_equal [nil], post.reader_ids
     assert_equal 1, post.readers.size
   end
 
+  def test_collection_empty_with_dirty_target
+    post = posts(:thinking)
+    assert_equal [], post.reader_ids
+    assert_empty post.readers
+    post.readers.reset
+    post.readers.build
+    assert_equal [nil], post.reader_ids
+    assert_not_empty post.readers
+  end
+
   def test_collection_size_twice_for_regressions
     post = posts(:thinking)
     assert_equal 0, post.readers.size
@@ -2573,6 +2583,70 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     end
   end
 
+  test "calling size on an association that has not been loaded performs a query" do
+    car = Car.create!
+    Bulb.create(car_id: car.id)
+
+    car_two = Car.create!
+
+    assert_queries(1) do
+      assert_equal 1, car.bulbs.size
+    end
+
+    assert_queries(1) do
+      assert_equal 0, car_two.bulbs.size
+    end
+  end
+
+  test "calling size on an association that has been loaded does not perform query" do
+    car = Car.create!
+    Bulb.create(car_id: car.id)
+    car.bulb_ids
+
+    car_two = Car.create!
+    car_two.bulb_ids
+
+    assert_no_queries do
+      assert_equal 1, car.bulbs.size
+    end
+
+    assert_no_queries do
+      assert_equal 0, car_two.bulbs.size
+    end
+  end
+
+  test "calling empty on an association that has not been loaded performs a query" do
+    car = Car.create!
+    Bulb.create(car_id: car.id)
+
+    car_two = Car.create!
+
+    assert_queries(1) do
+      assert_not_empty car.bulbs
+    end
+
+    assert_queries(1) do
+      assert_empty car_two.bulbs
+    end
+  end
+
+  test "calling empty on an association that has been loaded does not performs query" do
+    car = Car.create!
+    Bulb.create(car_id: car.id)
+    car.bulb_ids
+
+    car_two = Car.create!
+    car_two.bulb_ids
+
+    assert_no_queries do
+      assert_not_empty car.bulbs
+    end
+
+    assert_no_queries do
+      assert_empty car_two.bulbs
+    end
+  end
+
   class AuthorWithErrorDestroyingAssociation < ActiveRecord::Base
     self.table_name = "authors"
     has_many :posts_with_error_destroying,