From abe2cc859841712378bd0d9f5a0253afaf600e84 Mon Sep 17 00:00:00 2001
From: Min RK <benjaminrk@gmail.com>
Date: Wed, 8 Feb 2023 13:51:04 +0100
Subject: [PATCH] import downgrade test

rather than building old xeus-cling, which requires a downgrade of Python from 3.10 to 3.9,
which is _not_ supported,
run the build with a 3.9 pin.

This still results in patch-level downgrade of Python, major downgrade of openssl, etc.
---
 tests/conda/downgrade/environment.yml   | 11 +++++++++
 tests/conda/downgrade/verify            | 30 +++++++++++++++++++++++++
 tests/external/reproductions.repos.yaml |  6 -----
 3 files changed, 41 insertions(+), 6 deletions(-)
 create mode 100644 tests/conda/downgrade/environment.yml
 create mode 100755 tests/conda/downgrade/verify

diff --git a/tests/conda/downgrade/environment.yml b/tests/conda/downgrade/environment.yml
new file mode 100644
index 00000000..319f8d5d
--- /dev/null
+++ b/tests/conda/downgrade/environment.yml
@@ -0,0 +1,11 @@
+# originally xeus-cling@0.6.0
+# added python=3.9 pin because implicit downgrade of Python from 3.10 to 3.9 isn't allowed
+name: xeus-cling
+channels:
+  - conda-forge
+dependencies:
+  - python=3.9
+  - xeus-cling=0.6.0
+  - xtensor=0.20.8
+  - xtensor-blas=0.16.1
+  - notebook
diff --git a/tests/conda/downgrade/verify b/tests/conda/downgrade/verify
new file mode 100755
index 00000000..07b40940
--- /dev/null
+++ b/tests/conda/downgrade/verify
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+import json
+import pprint
+from subprocess import check_output
+
+
+def json_sh(cmd):
+    """Run a command that produces JSON on stdout and return the parsed result"""
+    buf = check_output(cmd)
+    return json.loads(buf.decode("utf8", "replace"))
+
+
+conda_pkg_list = json_sh(["conda", "list", "--json"])
+pprint.pprint(conda_pkg_list)
+# make it a dict
+pkgs = {pkg["name"]: pkg for pkg in conda_pkg_list}
+
+# base env resolved
+assert pkgs["python"]["version"].startswith("3.9"), pkgs["python"]
+assert "xeus-cling" in pkgs
+assert pkgs["xeus-cling"]["version"] == "0.6.0"
+
+# verify downgrade
+# this may be brittle, but it's unlikely any of these old versions
+# of packages will be rebuilt
+# xeus-cling 0.6.0 pins xeus 0.20, which pins openssl 1.1.1,
+# which in turn downgrades Python from >=3.9.16 to 3.9.6
+
+assert pkgs["openssl"]["version"].startswith("1.1.1"), pkgs["openssl"]["version"]
+assert pkgs["python"]["version"] == "3.9.6", pkgs["python"]["version"]
diff --git a/tests/external/reproductions.repos.yaml b/tests/external/reproductions.repos.yaml
index 74f1085c..55509a01 100644
--- a/tests/external/reproductions.repos.yaml
+++ b/tests/external/reproductions.repos.yaml
@@ -24,12 +24,6 @@
   url: https://github.com/binder-examples/requirements
   ref: python-3.7
   verify: python -c 'import matplotlib'
-# Test that custom channels and downgrades don't
-# get blocked by pinning
-- name: Xeus-Cling
-  url: https://github.com/QuantStack/xeus-cling
-  ref: 0.6.0
-  verify: jupyter kernelspec list
 # Zenodo record of https://github.com/binder-examples/requirements
 - name: 10.5281/zenodo.3242074
   url: 10.5281/zenodo.3242074