diff --git a/run.sh b/run.sh
index 76d8205..9200bb1 100755
--- a/run.sh
+++ b/run.sh
@@ -2,5 +2,5 @@
 
 set -o pipefail -o nounset -o errexit
 
-echo "${crond_line}" > "/etc/crontabs/root"
+echo "${crond_line:-}" > "/etc/crontabs/root"
 crond -f -L /dev/stdout
diff --git a/tests/test.sh b/tests/test.sh
index 7905058..324e10a 100644
--- a/tests/test.sh
+++ b/tests/test.sh
@@ -11,8 +11,13 @@ CONTAINER_NAME="test-crond-$$"
 
 # Test 1: Container starts and crond is running
 docker run -d --name "$CONTAINER_NAME" "$IMAGE"
-sleep 3
-if docker exec "$CONTAINER_NAME" pgrep crond > /dev/null 2>&1; then
+sleep 4
+if [ "$(docker inspect "$CONTAINER_NAME" --format='{{.State.Running}}')" != "true" ]; then
+  echo "FAIL: container exited prematurely"
+  echo "=== Container logs ==="
+  docker logs "$CONTAINER_NAME" 2>&1 || true
+  FAILED=$((FAILED + 1))
+elif docker exec "$CONTAINER_NAME" pgrep crond > /dev/null 2>&1; then
   echo "PASS: crond is running"
   PASSED=$((PASSED + 1))
 else