TST: add a custom pytest session header to make runtime state (free-threading, JIT) visible

bottleneck/conftest.py

@@ -1,8 +1,10 @@
+import textwrap
 from importlib.util import find_spec
 
 import pytest
 
 HAS_PYTEST_PARALLEL_RUN = find_spec("pytest_run_parallel") is not None
+HAS_RUNTIME_INTROSPECT = find_spec("runtime_introspect") is not None
 
 
 def pytest_configure(config):
@@ -29,3 +31,17 @@ def pytest_configure(config):
     @pytest.fixture
     def num_parallel_threads():
         return 1
+
+
+def pytest_report_header(config, start_path) -> list[str]:
+    if not HAS_RUNTIME_INTROSPECT:
+        return
+
+    from runtime_introspect import runtime_feature_set
+
+    fs = runtime_feature_set()
+    diagnostics = fs.diagnostics(features=["free-threading", "JIT"])
+    return [
+        "Runtime optional features state (snapshot):",
+        textwrap.indent("\n".join(diagnostics), "  "),
+    ]

pyproject.toml

@@ -68,6 +68,7 @@ doc = [
 ]
 test = [
     "pytest>=8.0.0",
+    "runtime-introspect>=0.4.1",
 ]
 concurrency = [
     { include-group = "test" },