diff --git a/tests/test_decorator.py b/tests/test_decorator.py
index 78f7e33..48b79ff 100644
--- a/tests/test_decorator.py
+++ b/tests/test_decorator.py
@@ -60,7 +60,9 @@ async def async_char(c: str = Depends(char)) -> str:
     @pytest.mark.asyncio
     async def test_use_cache(self) -> None:
         # arrange
-        from random import random as _random
+        from random import random as _rndm
+        def _random() -> float:
+            return _rndm()
 
         random = dependant(_random)
 
@@ -84,7 +86,6 @@ def cached(
         ) -> float:
             return r is x
 
-
         # act / assert
         assert await cached()