diff --git a/src/_zkapauthorizer/tests/test_controller.py b/src/_zkapauthorizer/tests/test_controller.py
index c30f73e889a5dd3de98a42dfd1a3a9517790a290..963f84e55f4327092b461d2a872f9a48d475848b 100644
--- a/src/_zkapauthorizer/tests/test_controller.py
+++ b/src/_zkapauthorizer/tests/test_controller.py
@@ -335,6 +335,8 @@ class PaymentControllerTests(TestCase):
                 ),
                 # TODO: It shouldn't need a default token count.  It should
                 # respect whatever was given on the first redemption attempt.
+                #
+                # https://github.com/PrivateStorageio/ZKAPAuthorizer/issues/93
                 default_token_count=num_tokens,
                 # The number of redemption groups must not change for
                 # redemption of a particular voucher.