If no --parallel option is given, it runs all the tests in one

ansible-playbook command line that is the original behavior.
If `--parallel` option is given, it runs each test per command
line. To run *.yml per command line in one container, '--parallel 1`
option is required.

src/tox_lsr/test_scripts/runcontainer.sh

@@ -318,11 +318,18 @@ run_playbooks() {
     setup_vault "$test_dir" "${test_pb_base}.yml"
     # shellcheck disable=SC2086
     pushd "$test_dir" > /dev/null
-    for pb in ${test_pb[@]}; do
+    if [ "$PARALLEL" -gt 0 ]; then
+        for pb in ${test_pb[@]}; do
+            ansible-playbook -vv ${CONTAINER_SKIP_TAGS:-} ${EXTRA_SKIP_TAGS:-} \
+                -i "$inv_file" ${vault_args:-} \
+                -e ansible_playbook_filepath="$(type -p ansible-playbook)" "$pb"
+        done
+    else
         ansible-playbook -vv ${CONTAINER_SKIP_TAGS:-} ${EXTRA_SKIP_TAGS:-} \
             -i "$inv_file" ${vault_args:-} \
-            -e ansible_playbook_filepath="$(type -p ansible-playbook)" "$pb"
-    done
+            -e ansible_playbook_filepath="$(type -p ansible-playbook)" \
+            "${test_pb[@]}"
+    fi
     popd > /dev/null
 }