test: split provider endpoint tests (#4961)

tests/test_provider_endpoints_models.py

@@ -0,0 +1,25 @@
+"""Provider endpoint model-selection tests.
+
+Covers ``_first_chat_model``: auto-picking the first usable chat model from a
+provider's model list, skipping embedding/tts/image models when possible.
+"""
+import pytest
+
+from src import endpoint_resolver as er
+
+
+# ── _first_chat_model: never auto-pick an embedding/tts/etc. model ──
+
+def test_first_chat_model_skips_non_chat():
+    models = ["text-embedding-ada-002", "whisper-1", "gpt-4o", "dall-e-3"]
+    assert er._first_chat_model(models) == "gpt-4o"
+
+
+def test_first_chat_model_falls_back_to_first_when_all_non_chat():
+    models = ["text-embedding-3-large", "text-embedding-3-small"]
+    assert er._first_chat_model(models) == "text-embedding-3-large"
+
+
+@pytest.mark.parametrize("models", [[], None])
+def test_first_chat_model_empty(models):
+    assert er._first_chat_model(models) is None