See also https://github.com/sarugaku/shellingham/issues/80

--- shellingham-1.5.4/tox.ini.orig
+++ shellingham-1.5.4/tox.ini
@@ -13,7 +13,7 @@
 [testenv]
 allowlist_externals = pipenv
 commands =
-    pipenv install --dev
+    python -m pytest
 
 [testenv:test]
 deps =