Improve `belongs_to touch: true` timestamp test

Round off time to a whole second value to compensate for databases
that don't support fractional timestamps. Also add a assertion to
check that the old record is touched when the association is cleared.

1 files changed, 21 insertions, 7 deletions

diff --git a/activerecord/test/cases/timestamp_test.rb b/activerecord/test/cases/timestamp_test.rb
index f42ecbb340..9d84f64c96 100644
--- a/activerecord/test/cases/timestamp_test.rb
+++ b/activerecord/test/cases/timestamp_test.rb
@@ -187,17 +187,11 @@ class TimestampTest < ActiveRecord::TestCase
 
     toy2 = klass.find(2)
     new_pet = toy2.pet
-    time = 3.days.ago
+    time = 3.days.ago.at_beginning_of_hour
 
     old_pet.update_columns(updated_at: time)
     new_pet.update_columns(updated_at: time)
 
-    old_pet.reload
-    new_pet.reload
-
-    assert_equal time, new_pet.updated_at
-    assert_equal time, old_pet.updated_at
-
     toy1.pet = new_pet
     toy1.save!
 
@@ -208,6 +202,26 @@ class TimestampTest < ActiveRecord::TestCase
     assert_not_equal time, old_pet.updated_at
   end
 
+  def test_clearing_association_touches_the_old_record
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; 'Toy'; end
+      belongs_to :pet, touch: true
+    end
+
+    toy = klass.find(1)
+    pet = toy.pet
+    time = 3.days.ago.at_beginning_of_hour
+
+    pet.update_columns(updated_at: time)
+
+    toy.pet = nil
+    toy.save!
+
+    pet.reload
+
+    assert_not_equal time, pet.updated_at
+  end
+
   def test_timestamp_attributes_for_create
     toy = Toy.first
     assert_equal toy.send(:timestamp_attributes_for_create), [:created_at, :created_on]