fix(test): make pytest config parse on current pytest

pyproject.toml

@@ -71,16 +71,17 @@ ignore = ["ANN101", "ANN102", "ANN401"]
 [tool.ruff.isort]
 known-first-party = ["rulebook_ai"]
 
-[tool.pytest]
+[tool.pytest.ini_options]
 testpaths = ["tests"]
+pythonpath = ["src"]
 python_files = ["test_*.py"]
 python_classes = ["Test*"]
 python_functions = ["test_*"]
 markers = [
     "unit: marks tests as unit tests",
     "integration: marks tests as integration tests",
 ]
-addopts = "-v"
+addopts = ["-v"]
 
 [tool.mypy]
 python_version = "3.9"

tests/unit/test_pytest_config.py

@@ -0,0 +1,30 @@
+"""Regression tests for pytest configuration."""
+
+import subprocess
+import sys
+from pathlib import Path
+
+
+def test_pytest_config_supports_collect_only_from_repo_root() -> None:
+    """The pyproject pytest config should not fail during argument parsing."""
+    repo_root = Path(__file__).resolve().parents[2]
+
+    result = subprocess.run(  # noqa: S603
+        [
+            sys.executable,
+            "-m",
+            "pytest",
+            "--collect-only",
+            "tests/unit/test_state_files.py",
+            "-q",
+        ],
+        cwd=repo_root,
+        capture_output=True,
+        text=True,
+        timeout=30,
+    )
+
+    if result.returncode != 0:
+        raise AssertionError(result.stderr)
+    if "test_state_files.py" not in result.stdout:
+        raise AssertionError(result.stdout)