1 files changed, 16 insertions, 0 deletions
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
index c450b1beb5..026a7fe635 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -514,6 +514,15 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert_equal(post.taggings.count, post.taggings_count)
   end
 
+  def test_update_counter_caches_on_destroy
+    post = posts(:welcome)
+    tag  = post.tags.create!(name: 'doomed')
+
+    assert_difference 'post.reload.taggings_count', -1 do
+      tag.tagged_posts.destroy(post)
+    end
+  end
+
   def test_replace_association
     assert_queries(4){posts(:welcome);people(:david);people(:michael); posts(:welcome).people(true)}
 
@@ -808,6 +817,13 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert author.named_categories(true).include?(category)
   end
 
+  def test_collection_exists
+    author   = authors(:mary)
+    category = Category.create!(author_ids: [author.id], name: "Primary")
+    assert category.authors.exists?(id: author.id)
+    assert category.reload.authors.exists?(id: author.id)
+  end
+
   def test_collection_delete_with_nonstandard_primary_key_on_belongs_to
     author   = authors(:mary)
     category = author.named_categories.create(:name => "Primary")