Conditionally set matplotlib backend to Agg only if running in GitHub Actions and OS is windows, since GHA macos apparently doesn't like Agg backend (https://github.com/softwareengineerprogrammer/GEOPHIRES/actions/runs/14779862524/job/41496253000\#step:5:721)

Author: softwareengineerprogrammer

.github/workflows/github-actions.yml

@@ -119,10 +119,6 @@ jobs:
     - name: test
       env:
         TOXPYTHON: '${{ matrix.toxpython }}'
-
-        # Prevent intermittent GitHub Actions Windows failures per https://github.com/NREL/GEOPHIRES-X/issues/365
-        MPLBACKEND: 'Agg'
-
       run: >
         tox -e ${{ matrix.tox_env }} -v
 

tests/__init__.py

@@ -1,5 +1,10 @@
-import matplotlib
+import os
 
-# Backend should be 'Agg' in GitHub Actions to prevent intermittent Windows failures
-# per https://github.com/NREL/GEOPHIRES-X/issues/365
-print(f'[DEBUG] matplotlib backend: {matplotlib.get_backend()}')
+import matplotlib as mpl
+
+if os.name == 'nt' and 'TOXPYTHON' in os.environ:
+    # Backend should be 'Agg' in GitHub Actions to prevent intermittent Windows failures
+    # per https://github.com/NREL/GEOPHIRES-X/issues/365
+    mpl.use('Agg')
+
+print(f'[DEBUG] matplotlib backend: {mpl.get_backend()}')