diff --git a/concourse/test.sh b/concourse/test.sh
index a72027a9..0e2eab76 100755
--- a/concourse/test.sh
+++ b/concourse/test.sh
@@ -16,7 +16,8 @@ function _main() {
     install_plpython3
 
     source "$CI_REPO_DIR/common/entry_common.sh"
-    alias su='sudo su'  # for `su gpadmin` in start_gpdb
+    sudo passwd --delete gpadmin  # for `su gpadmin` in start_gpdb
+    alias su='sudo su'
     start_gpdb
     source "$HOME/.bashrc"  # for gpdemo-env.sh