pytest: use PYTHONPATH, not ., as first entry in sys.path (#166)

Python 3.11 has the `-P` flag. For other Pythons, we invoke `pytest`
directly, which seems to handle PYTHONPATH correctly.

Closes #165

Author: stefanv

spin/cmds/meson.py

@@ -363,9 +363,13 @@ def test(ctx, pytest_args, n_jobs, tests, verbose, coverage=False, gcov=False):
         ]
 
     print(f'$ export PYTHONPATH="{site_path}"')
+
+    if sys.version_info[:2] >= (3, 11):
+        cmd = [sys.executable, "-P", "-m", "pytest"]
+    else:
+        cmd = ["pytest"]
     _run(
-        [sys.executable, "-m", "pytest", f"--rootdir={site_path}"] + list(pytest_args),
-        cwd=site_path,
+        cmd + list(pytest_args),
         replace=True,
     )