CI: only use virtualenv if it is installed (helps with caching)

Author: agarciadom

.github/workflows/local-playground-test.yml

@@ -3,10 +3,13 @@ name: Test local Playground
 on:
   push:
     branches: [ "main" ]
-    paths: [ "mkdocs/docs/playground/**", ".github/workflows/local-playground-test.yml" ]
+    paths: &paths
+      - mkdocs/docs/playground/**
+      - mkdocs/docs/serve-no-livereload.sh
+      - .github/workflows/local-playground-test.yml
   pull_request:
     branches: [ "main" ]
-    paths: [ "mkdocs/docs/playground/**", ".github/workflows/local-playground-test.yml" ]
+    paths: *paths
   workflow_dispatch:
 
 jobs:

mkdocs/serve-no-livereload.sh

@@ -5,12 +5,15 @@ set -e
 # Go to the directory with this script
 cd "$(dirname "$(readlink -f "$0")")"
 
-# Create a Python virtualenv if it does not exist yet
-if ! test -d env; then
-  virtualenv -p python3 env
+# Create a Python virtualenv if we have the tool installed
+# and it does not exist yet.
+if which virtualenv; then
+  if ! test -d env; then
+    virtualenv -p python3 env
+  fi
+  source env/bin/activate
 fi
 
 # Serve the website without live reloading (useful for tests)
-source env/bin/activate
 pip install -r requirements.txt
 mkdocs serve --no-livereload