diff --git a/Jenkinsfile b/Jenkinsfile
index b7361c9..67cd591 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -20,7 +20,9 @@ pipeline {
 
     stages {
         stage('Docker image warmup') {
-            sh "docker build -f Dockerfile.test"
+            steps {
+                sh "docker build -f Dockerfile.test"
+            }
         }
 
         stage('R6RS') {