1 files changed, 6 insertions, 0 deletions
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
index c0be7dfdcc..7e070e1746 100644
--- a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -858,4 +858,10 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
     assert_equal new_developer.name, "Marcelo"
     assert_equal new_developer.salary, 90_000
   end
+
+  def test_include_method_in_has_and_belongs_to_many_association_should_return_true_for_instance_added_with_build
+    project = Project.new
+    developer = project.developers.build
+    assert project.developers.include?(developer)
+  end
 end