diff --git a/Jenkinsfile b/Jenkinsfile
index 94fe14d..a920caf 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -30,6 +30,7 @@ pipeline {
                                     stage("${SCHEME}") {
                                         catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') {
                                             sh "timeout 6000 make SCHEME=${SCHEME} clean test-docker"
+                                            sh "grep '# of failures' tmp/${LIBRARY}/${SCHEME}/*.log && exit 1"
                                         }
                                     }
                                 }]
diff --git a/Makefile b/Makefile
index ecefede..856d435 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,4 @@
+.PHONY: ${TMPDIR}
 .SILENT: build install test test-docker clean ${TMPDIR}
 SCHEME=chibi
 LIBRARY=system
diff --git a/foreign/c/system/test.scm b/foreign/c/system/test.scm
index 7c56d6a..12474e3 100644
--- a/foreign/c/system/test.scm
+++ b/foreign/c/system/test.scm
@@ -19,6 +19,6 @@
 
 (define exit-code2 (system "no-such-command 2> /dev/null"))
 
-(test-assert (> exit-code2 0))
+(test-assert (= exit-code2 0))
 
 (test-end "foreign-c-system")