Fix installers and tests

setup.sh

@@ -41,11 +41,11 @@ done
 
 # ensure Python packages used by the CLI are available
 for py in InquirerPy rich; do
-  python3 - <<EOF >/dev/null 2>&1
+  if ! python3 - <<EOF >/dev/null 2>&1
 import importlib.util, sys
 sys.exit(0 if importlib.util.find_spec('$py') else 1)
 EOF
-  if [ $? -ne 0 ]; then
+  then
     pip install --user "$py"
   fi
 done