diff --git a/Jenkinsfile b/Jenkinsfile
index d271cdc..09b9ca3 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -21,7 +21,9 @@ pipeline {
 
     stages {
         stage('Docker image warmup') {
-            sh "docker build -f Dockerfile.test"
+            steps {
+                sh "docker build -f Dockerfile.test"
+            }
         }
 
         stage('R6RS tests') {