diff --git a/tests/test_model_string_invariants.py b/tests/test_model_string_invariants.py
new file mode 100644
index 0000000..a717335
--- /dev/null
+++ b/tests/test_model_string_invariants.py
@@ -0,0 +1,14 @@
+import pytest
+
+def normalize_model_name(name: str) -> str:
+    if not name or not isinstance(name, str):
+        return ""
+    return name.strip()
+
+def test_model_name_trimming():
+    assert normalize_model_name("  meta-llama/Llama-3-70b-chat-hf  ") == "meta-llama/Llama-3-70b-chat-hf"
+    assert normalize_model_name("mistralai/Mixtral-8x7B-Instruct-v0.1") == "mistralai/Mixtral-8x7B-Instruct-v0.1"
+
+def test_empty_model_name():
+    assert normalize_model_name("") == ""
+    assert normalize_model_name("   ") == ""