tests: add a script to run tests from a Python distribution

It is pretty basic. But it gets the job done.

We are currently looking at 52 test failures on Linux.

Author: indygreg

Diff for: test-distribution.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+"""Script to run Python tests from a distribution archive."""
+
+import json
+import pathlib
+import subprocess
+import sys
+import tarfile
+import tempfile
+
+import zstandard
+
+
+def main(args):
+    if not args:
+        print("Usage: test-distribution.py path/to/distribution.tar.zst")
+        return 1
+
+    distribution_path = args[0]
+
+    with tempfile.TemporaryDirectory() as td:
+        td = pathlib.Path(td)
+
+        with open(distribution_path, "rb") as fh:
+            dctx = zstandard.ZstdDecompressor()
+            with dctx.stream_reader(fh) as reader:
+                with tarfile.open(mode="r|", fileobj=reader) as tf:
+                    tf.extractall(td)
+
+        root = td / "python"
+
+        python_json = root / "PYTHON.json"
+
+        with python_json.open("rb") as fh:
+            info = json.load(fh)
+
+        test_args = [
+            str(root / info["python_exe"]),
+            str(root / info["run_tests"]),
+        ]
+
+        test_args.extend(args[1:])
+
+        return subprocess.run(test_args).returncode
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))