add test

Author: donbobka

test/transaction_test.rb

@@ -69,5 +69,13 @@ def pg_lock_count
       end
       assert_equal(0, pg_lock_count)
     end
+
+    specify 'transaction level locks fail if not in transaction' do
+      Tag.with_advisory_lock 'test', transaction: true do
+        raise 'should not get here'
+      end
+
+      assert_match(/#{Regexp.escape('requires transaction')}/, exception.message)
+    end
   end
 end