diff --git a/scripts/testcase/testcase-watchdog-cilium-faststart-unhealthy-v2.sh b/scripts/testcase/testcase-watchdog-cilium-faststart-unhealthy-v2.sh
index 6ba0027ad..b2b07fbe4 100644
--- a/scripts/testcase/testcase-watchdog-cilium-faststart-unhealthy-v2.sh
+++ b/scripts/testcase/testcase-watchdog-cilium-faststart-unhealthy-v2.sh
@@ -59,6 +59,13 @@ function before_test() {
   }
   export -f curl
 
+  # shellcheck disable=SC2317
+  function sleep() {
+    echo "[MOCK called] sleep $*"
+    echo "[MOCK] this test expects a delay during fast start."
+  }
+  export -f sleep
+
 }
 
 function verify() {
diff --git a/scripts/testcase/testcase-watchdog-cilium-faststart-v2.sh b/scripts/testcase/testcase-watchdog-cilium-faststart-v2.sh
index 1a83a9358..22c21ebb6 100644
--- a/scripts/testcase/testcase-watchdog-cilium-faststart-v2.sh
+++ b/scripts/testcase/testcase-watchdog-cilium-faststart-v2.sh
@@ -56,6 +56,13 @@ function before_test() {
   }
   export -f curl
 
+  # shellcheck disable=SC2317
+  function sleep() {
+    echo "[MOCK called] sleep $*"
+    echo "[MOCK] this test expects a delay during fast start."
+  }
+  export -f sleep
+
 }
 
 function verify() {