test: add tests for cached ModelParamHelper logging args

Verify cached frozenset matches dynamic computation and that
prompt content keys (messages, prompt, input) are excluded from
logged model parameters.

tests/test_litellm/test_model_param_helper.py

@@ -0,0 +1,33 @@
+from litellm.litellm_core_utils.model_param_helper import ModelParamHelper
+
+
+def test_cached_relevant_logging_args_matches_dynamic():
+    """Verify the cached frozenset matches the dynamically computed set."""
+    cached = ModelParamHelper._relevant_logging_args
+    dynamic = ModelParamHelper._get_relevant_args_to_use_for_logging()
+    assert cached == dynamic
+    assert isinstance(cached, frozenset)
+
+
+def test_get_standard_logging_model_parameters_filters():
+    """Verify model parameters are filtered to only supported keys."""
+    params = {"temperature": 0.7, "messages": [{"role": "user"}], "max_tokens": 100}
+    result = ModelParamHelper.get_standard_logging_model_parameters(params)
+    assert "temperature" in result
+    assert "max_tokens" in result
+    assert "messages" not in result  # excluded prompt content
+
+
+def test_get_standard_logging_model_parameters_excludes_prompt_content():
+    """Verify all prompt content keys are excluded."""
+    params = {
+        "messages": [{"role": "user", "content": "hi"}],
+        "prompt": "hello",
+        "input": "test",
+        "temperature": 0.5,
+    }
+    result = ModelParamHelper.get_standard_logging_model_parameters(params)
+    assert "messages" not in result
+    assert "prompt" not in result
+    assert "input" not in result
+    assert result == {"temperature": 0.5}