diff --git a/tests/venv/start/postBuild/postBuild b/tests/venv/start/postBuild/postBuild
index ccd2f8e3..5d63e932 100755
--- a/tests/venv/start/postBuild/postBuild
+++ b/tests/venv/start/postBuild/postBuild
@@ -2,3 +2,5 @@
 
 # this value should not be visible in `verify`
 export TEST_START_VAR="var is set by postBuild"
+
+echo 'Done!' > $HOME/postbuild.txt
diff --git a/tests/venv/start/postBuild/verify b/tests/venv/start/postBuild/verify
index 2daa9539..5fd16f8d 100755
--- a/tests/venv/start/postBuild/verify
+++ b/tests/venv/start/postBuild/verify
@@ -1,7 +1,6 @@
 #!/bin/bash
 set -euo pipefail
-jupyter nbextension list | grep 'jupyter-leaflet' | grep enabled
-
+grep 'Done!' $HOME/postbuild.txt
 # set value of TEST_START_VAR to empty string when it is not defined
 if [ "${TEST_START_VAR:-}" != "var is set" ]
 then