Bump GAMS version in nightly CI worklow (#892)

* Run nightly workflow on GAMS file changes and labeled PRs
* Import numpy and partial so nightly test can use it

.github/workflows/nightly.yaml

@@ -9,9 +9,19 @@ on:
   schedule:
   # 05:00 UTC = 06:00 CET = 07:00 CEST
   - cron: "0 5 * * *"
+  pull_request_target:
+    paths:
+      - '**.gms'
+      - '**.gpr'
+      - '**.gdx'
+    types:
+     - labeled
 
 env:
-  GAMS_VERSION: 29.1.0
+  # Version used until 2024-11-20; disabled
+  # GAMS_VERSION: 29.1.0
+  # First version including a macOS arm64 distribution
+  GAMS_VERSION: 43.4.1
   # See description in lint.yml
   depth: 100
 

message_ix/tests/test_nightly.py

@@ -1,6 +1,9 @@
 """Slow-running tests for nightly continuous integration."""
 
+from functools import partial  # noqa: F401, is used through `case["test"]` below
+
 import ixmp
+import numpy as np  # noqa: F401, same as above
 import pytest
 
 import message_ix