Add unit tests for _benchmark_worker subprocess script

5 tests covering module-level argv parsing, project_root derivation,
benchmark plugin and trace decorator imports, and __main__ guard.

packages/codeflash-python/tests/test_benchmark_worker.py

@@ -0,0 +1,60 @@
+"""Tests for the benchmark execution subprocess worker."""
+
+from __future__ import annotations
+
+import importlib
+import sys
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def _patch_argv(monkeypatch, tmp_path):
+    """Ensure sys.argv has enough entries for module-level reads."""
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        [
+            "_benchmark_worker.py",
+            str(tmp_path / "benchmarks"),
+            str(tmp_path / "tests"),
+            str(tmp_path / "trace.db"),
+        ],
+    )
+
+
+@pytest.fixture
+def _worker_mod():
+    """Import the benchmark worker module (needs patched argv)."""
+    mod_name = "codeflash_python.benchmarking._benchmark_worker"
+    if mod_name in sys.modules:
+        return importlib.reload(sys.modules[mod_name])
+    return importlib.import_module(mod_name)
+
+
+class TestBenchmarkWorkerModule:
+    """Tests for the benchmark worker module structure."""
+
+    def test_module_level_args_parsed(self, _worker_mod, tmp_path) -> None:
+        """Module-level argv reads produce correct paths."""
+        assert str(tmp_path / "benchmarks") == _worker_mod.benchmarks_root
+        assert str(tmp_path / "tests") == _worker_mod.tests_root
+        assert str(tmp_path / "trace.db") == _worker_mod.trace_file
+
+    def test_project_root_is_cwd(self, _worker_mod) -> None:
+        """project_root defaults to Path.cwd()."""
+        assert Path.cwd() == _worker_mod.project_root
+
+    def test_imports_benchmark_plugin(self, _worker_mod) -> None:
+        """Module imports the codeflash benchmark plugin."""
+        assert hasattr(_worker_mod, "codeflash_benchmark_plugin")
+
+    def test_imports_codeflash_trace(self, _worker_mod) -> None:
+        """Module imports the codeflash trace decorator."""
+        assert hasattr(_worker_mod, "codeflash_trace")
+
+    def test_not_main_skips_pytest(self, _worker_mod) -> None:
+        """When not __main__, pytest.main is not called."""
+        assert _worker_mod.__name__ != "__main__"