Separate out notebooks and not notebooks in tox (#342)

.github/workflows/main.yml

@@ -38,7 +38,7 @@ jobs:
         - linux: py311
         - windows: py310-online
         - macos: py39
-        - linux: build_docs
+        - linux: build_docs-notebooks
           pytest: false
           libraries:
             apt:

tox.ini

@@ -1,12 +1,22 @@
 [tox]
-envlist = py{39,310,311}{,-devdeps,-oldestdeps,-online},build_docs,codestyle
+envlist = py{39,310,311}{,-devdeps,-oldestdeps,-online},build_docs{,-notebooks},codestyle
 requires =
     setuptools >= 30.3.0
     pip >= 21.0.1
     #tox-pypi-filter >= 0.12
 
 [testenv]
-passenv = CC
+# Pass through the following environment variables which may be needed for the CI
+pass_env =
+    # A variable to tell tests we are on a CI system
+    CI
+    # Custom compiler locations (such as ccache)
+    CC
+    # Location of locales (needed by sphinx on some systems)
+    LOCALE_ARCHIVE
+    # If the user has set a LC override we should follow it
+    # (note LANG is automatically passed through by tox)
+    LC_ALL
 setenv =
     MPLBACKEND = agg
     COLUMNS = 180
@@ -49,14 +59,15 @@ commands_pre =
     oldestdeps: pip install -r requirements-min.txt cryptography<42 jsonschema==4.0.1
     pip freeze --all --no-input
 
-[testenv:build_docs]
+[testenv:build_docs{,-notebooks}]
 changedir = docs
 extras = docs
 description = Invoke sphinx-build to build the HTML docs
 commands =
     pip freeze --all --no-input
     # Disable parallel here due to https://github.com/astropy/astropy/issues/14916
-    sphinx-build -j 1 --color -W --keep-going -b html -d _build/.doctrees . _build/html {posargs}
+    !notebooks: sphinx-build -j 1 --color -W --keep-going -b html -d _build/.doctrees . _build/html -D nb_execution_mode=off {posargs}
+    notebooks: sphinx-build -j 1 --color -W --keep-going -b html -d _build/.doctrees . _build/html {posargs}
     python -c 'import pathlib; print("Documentation available under file://\{0\}".format(pathlib.Path(r"{toxinidir}") / "docs" / "_build" / "index.html"))'
 
 [testenv:codestyle]