diff --git a/selfdrive/car/tests/test_can_fingerprint.py b/selfdrive/car/tests/test_can_fingerprint.py
index 6f9922129f..e2899246f1 100644
--- a/selfdrive/car/tests/test_can_fingerprint.py
+++ b/selfdrive/car/tests/test_can_fingerprint.py
@@ -1,4 +1,5 @@
 from parameterized import parameterized
+from types import SimpleNamespace
 
 from openpilot.selfdrive.car.can_definitions import CanData
 from openpilot.selfdrive.car.car_helpers import FRAME_FINGERPRINT, can_fingerprint
@@ -15,7 +16,12 @@ class TestCanFingerprint:
              for address, length in fingerprint.items() for src in (0, 1)]
 
       fingerprint_iter = iter([can])
-      car_fingerprint, finger = can_fingerprint(lambda: next(fingerprint_iter, []))  # noqa: B023
+      def drain(wait_for_one=False):
+        ret = next(fingerprint_iter, [CanData(1, b'\x00', 128)])  # noqa: B023
+        return [ret]
+
+      logcan = SimpleNamespace(drain=drain)
+      car_fingerprint, finger = can_fingerprint(logcan)
 
       assert car_fingerprint == car_model
       assert finger[0] == fingerprint
@@ -46,11 +52,12 @@ class TestCanFingerprint:
       with subtests.test(expected_frames=expected_frames, car_model=car_model):
         frames = 0
 
-        def test():
+        def drain(wait_for_one=False):
           nonlocal frames
           frames += 1
-          return can  # noqa: B023
+          return [can]  # noqa: B023
 
-        car_fingerprint, _ = can_fingerprint(test)
+        logcan = SimpleNamespace(drain=drain)
+        car_fingerprint, _ = can_fingerprint(logcan)
         assert car_fingerprint == car_model
         assert frames == expected_frames + 2  # TODO: fix extra frames