diff --git a/activerecord/lib/active_record/test_fixtures.rb b/activerecord/lib/active_record/test_fixtures.rb
index c88e4fc61051f..d631b05db6eae 100644
--- a/activerecord/lib/active_record/test_fixtures.rb
+++ b/activerecord/lib/active_record/test_fixtures.rb
@@ -86,6 +86,9 @@ def setup_fixture_accessors(fixture_set_names = nil)
         include methods
       end
 
+      # Prevents automatically wrapping each specified test in a transaction,
+      # to allow application logic transactions to be tested in a top-level
+      # (non-nested) context.
       def uses_transaction(*methods)
         @uses_transaction = [] unless defined?(@uses_transaction)
         @uses_transaction.concat methods.map(&:to_s)