diff --git a/tests/conftest.py b/tests/conftest.py
index 29b92252a8ebb62ece008fda8a744f7a59d4ecc0..be456608c2721673b18738c918ed8cdc0c84b559 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -30,7 +30,9 @@ def cache_yaml(monkeypatch):
         # Create a unique cache key for direct YAML strings
         # and file descriptors
         if isinstance(yaml_payload, str):
-            key = hashlib.md5(yaml_payload.encode("utf-8")).hexdigest()
+            yaml_payload = yaml_payload.encode("utf-8")
+        if isinstance(yaml_payload, bytes):
+            key = hashlib.md5(yaml_payload).hexdigest()
         else:
             key = yaml_payload.name