diff --git a/tests/common/test_transaction.py b/tests/common/test_transaction.py
index 7b8dde99..ffc44879 100644
--- a/tests/common/test_transaction.py
+++ b/tests/common/test_transaction.py
@@ -93,7 +93,7 @@ def test_output_serialization(user_Ed25519, user_pub):
             'uri': user_Ed25519.condition_uri,
             'details': {
                 'type': 'ed25519-sha-256',
-                'public_key': b58encode(user_Ed25519.public_key),
+                'public_key': b58encode(user_Ed25519.public_key).decode(),
             },
         },
         'public_keys': [user_pub],