diff --git a/tests-ng/uninstall.sh b/tests-ng/uninstall.sh
index 8da29fe..0066262 100755
--- a/tests-ng/uninstall.sh
+++ b/tests-ng/uninstall.sh
@@ -7,10 +7,11 @@
 #
 
 ## start-cookie
-set -e
+set -euo errtrace pipefail
 cur=$(cd "$(dirname "${0}")" && pwd)
 ddpath="${cur}/../"
-export PYTHONPATH="${ddpath}:${PYTHONPATH}"
+PPATH="{PYTHONPATH:-}"
+export PYTHONPATH="${ddpath}:${PPATH}"
 altbin="python3 -m dotdrop.dotdrop"
 if hash coverage 2>/dev/null; then
   mkdir -p coverages/