diff --git a/tests/local_testing/conftest.py b/tests/local_testing/conftest.py
index 6a746041f15..5389dd96aed 100644
--- a/tests/local_testing/conftest.py
+++ b/tests/local_testing/conftest.py
@@ -22,6 +22,19 @@ sys.path.insert(
 )  # Adds the parent directory to the system path
 import litellm
 
+# ``litellm.model_cost`` is loaded at import time from the URL pinned to
+# ``main`` (``LITELLM_MODEL_COST_MAP_URL``).  The in-tree backup ships with
+# this branch and can include pricing entries that main has not yet picked
+# up (e.g. an upstream provider rotates a model id and the test cassette
+# records the new name).  Backfill any entries that are missing from the
+# remote-fetched map so cost-calculator lookups in tests succeed against
+# the cassette state the branch is being tested with.
+from litellm.litellm_core_utils.get_model_cost_map import GetModelCostMap
+
+for _k, _v in GetModelCostMap.load_local_model_cost_map().items():
+    litellm.model_cost.setdefault(_k, _v)
+del _k, _v
+
 from tests._vcr_conftest_common import (  # noqa: E402,F401
     VerboseReporterState,
     _pin_multipart_boundary,