chore: disable python 3.9 coverage (#2178)

Author: stevenh

.github/workflows/ci.yml

@@ -204,6 +204,7 @@ jobs:
           enable-cache: true
 
       - run: uv sync --package pydantic-ai-slim --only-dev
+      - run: rm coverage/.coverage.*-py3.9-* # Exclude 3.9 coverage as it gets the wrong line numbers, causing invalid failures.
       - run: uv run coverage combine coverage
 
       - run: uv run coverage html --show-contexts --title "PydanticAI coverage for ${{ github.sha }}"

tests/test_direct.py

@@ -143,7 +143,7 @@ def test_model_request_stream_sync_without_context_manager():
 
     with pytest.raises(RuntimeError, match=expected_error_msg):
         for _ in stream_cm:
-            break
+            break  # pragma: no cover
 
 
 def test_model_request_stream_sync_exception_in_stream():