diff --git a/tox.ini b/tox.ini
index 52500f21..263c8edd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -64,7 +64,8 @@ passenv =
     LIBRARY_PATH
 set_env =
     dev: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/liberfa/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
-
+allowlist_externals =
+    ls
 args_are_paths = false
 change_dir = pyargs: {env:HOME}
 extras =
@@ -83,6 +84,7 @@ pass_env =
 commands_pre =
     dev: pip install -r requirements-dev.txt -U --upgrade-strategy eager
     pip freeze
+    ls -l /tmp/data/*
 commands =
     pytest \
     warnings: -W error \