MAINT - Add CI env check for a11y tests (#1915)

.github/workflows/CI.yml

@@ -106,7 +106,6 @@ jobs:
       - name: "Run accessibility tests with playwright 🎭"
         # build PST, build docs, then run a11y-tests
         run: python -Im tox run -e py312-docs,a11y-tests
-        continue-on-error: true
 
   # Build our docs (PST) on major OSes and check for warnings
   build-site:

tox.ini

@@ -72,15 +72,18 @@ commands =
 [testenv:a11y-tests]
 description = run accessibility tests with Playwright and axe-core
 base_python = py312 # keep in sync with tests.yml
+pass_env = GITHUB_ACTIONS # so we can check if this is run on GitHub Actions
 extras = 
     test
     a11y
 depends = 
     compile, 
     py312-docs
-allowlist_externals=playwright
+allowlist_externals=
+    playwright
+    bash
 commands = 
-    playwright install 
+    bash -c 'if [[ "{env:GITHUB_ACTIONS:}" == "true" ]]; then playwright install --with-deps; else playwright install; fi'
     pytest -m "a11y" {posargs}
 
 # build PST documentation with the default or a specific Sphinx version