diff --git a/tests/utils.py b/tests/utils.py
index eefff60..8dbdc67 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -40,7 +40,7 @@ def generate_block(planet):
     from transactions.common.crypto import generate_key_pair
 
     alice = generate_key_pair()
-    tx = Create.generate([alice.public_key], [([alice.public_key], 1)], assets=None).sign([alice.private_key])
+    tx = Create.generate([alice.public_key], [([alice.public_key], 1)], assets=[{"data":None}]).sign([alice.private_key])
 
     code, message = planet.write_transaction(tx, BROADCAST_TX_COMMIT)
     assert code == 202