diff --git a/tests/unit_tests/model/test_instrument.py b/tests/unit_tests/model/test_instrument.py
index 7dd6723e787d..38d7ed060d12 100644
--- a/tests/unit_tests/model/test_instrument.py
+++ b/tests/unit_tests/model/test_instrument.py
@@ -175,7 +175,7 @@ def test_crypto_perpetual_instrument_to_dict(self):
             "size_increment": "1",
             "max_quantity": None,
             "min_quantity": None,
-            "max_notional": "10_000_000.00 USD",
+            'max_notional': '10000000.00 USD',
             "min_notional": "1.00 USD",
             "max_price": "1000000.0",
             "min_price": "0.5",