diff --git a/tests/venv/binder-dir/binder/postBuild b/tests/venv/binder-dir/binder/postBuild
index 28b840f0f..a88d62594 100755
--- a/tests/venv/binder-dir/binder/postBuild
+++ b/tests/venv/binder-dir/binder/postBuild
@@ -1,2 +1,2 @@
 #!/bin/bash
-jupyter nbextension enable --py --sys-prefix ipyleaflet
+echo 'Done!' > $HOME/postbuild.txt
\ No newline at end of file
diff --git a/tests/venv/binder-dir/verify b/tests/venv/binder-dir/verify
index 64aff2881..b1b4ab85d 100755
--- a/tests/venv/binder-dir/verify
+++ b/tests/venv/binder-dir/verify
@@ -4,3 +4,5 @@ which gfortran
 test -z $(pip list | grep scipy)
 jupyter nbextension list
 jupyter nbextension list | grep 'jupyter-leaflet' | grep enabled
+
+grep 'Done!' $HOME/postbuild.txt
diff --git a/tests/venv/start/postBuild/postBuild b/tests/venv/start/postBuild/postBuild
index dbf155299..5d63e932a 100755
--- a/tests/venv/start/postBuild/postBuild
+++ b/tests/venv/start/postBuild/postBuild
@@ -3,4 +3,4 @@
 # this value should not be visible in `verify`
 export TEST_START_VAR="var is set by postBuild"
 
-jupyter nbextension enable --py --sys-prefix ipyleaflet
+echo 'Done!' > $HOME/postbuild.txt
diff --git a/tests/venv/start/postBuild/verify b/tests/venv/start/postBuild/verify
index 2daa95391..5fd16f8d0 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