diff --git a/test/form_builder/association_test.rb b/test/form_builder/association_test.rb
index 562f4d4e..2b0dae5d 100644
--- a/test/form_builder/association_test.rb
+++ b/test/form_builder/association_test.rb
@@ -131,6 +131,7 @@ class AssociationTest < ActionView::TestCase
   test 'builder creates a select with multiple options for collection associations' do
     with_association_for @user, :tags
     assert_select 'form select.select#user_tag_ids'
+    assert_select 'form select[multiple=multiple]'
     assert_select 'form select option[value=1]', 'Tag 1'
     assert_select 'form select option[value=2]', 'Tag 2'
     assert_select 'form select option[value=3]', 'Tag 3'