diff --git a/test/unit/test_keccak.py b/test/unit/test_keccak.py
index c32a74f8d6..cd7b068ed2 100644
--- a/test/unit/test_keccak.py
+++ b/test/unit/test_keccak.py
@@ -38,5 +38,10 @@ class TestKeccak(unittest.TestCase):
     out = Tensor(b"abc").keccak()
     self.assertEqual(bytes(out.tolist()), bytearray.fromhex("3a985da74fe225b2 045c172d6bd390bd 855f086e3e9d525b 46bfe24511431532"))
 
+  @unittest.expectedFailure
+  def test_long(self):
+    out = Tensor(b"\x00" * 4096).keccak()
+    self.assertEqual(bytes(out.tolist()), hashlib.shake_128(b"\x00" * 4096).digest(16))
+
 if __name__ == "__main__":
   unittest.main()