diff --git a/artiq/gateware/test/rtio/test_fastlink.py b/artiq/gateware/test/rtio/test_fastlink.py
index 4304963d6..3733e8205 100644
--- a/artiq/gateware/test/rtio/test_fastlink.py
+++ b/artiq/gateware/test/rtio/test_fastlink.py
@@ -83,4 +83,8 @@ class TestFastino(unittest.TestCase):
             vcd_name="fastlink.vcd")
         self.assertEqual(len(frame), 7*14//2)
         self.assertEqual([d[0] for d in frame], [3, 0, 1, 3, 2, 0, 3] * 7)
+        self.assertEqual(ref, frame)
         print(frame)
+
+
+ref = [[3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 2, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 1, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 2, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 1, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 2, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 1, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 2, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [1, 3, 3, 3, 3, 3, 3, 0], [3, 3, 3, 3, 3, 3, 3, 0], [2, 3, 3, 3, 3, 3, 3, 0], [0, 3, 3, 3, 3, 3, 3, 0], [3, 3, 1, 1, 1, 2, 1, 0]]