diff --git a/drydocker/roundcubemail/test_unit.sh b/drydocker/roundcubemail/test_unit.sh
index c15c63c..f5ec01d 100755
--- a/drydocker/roundcubemail/test_unit.sh
+++ b/drydocker/roundcubemail/test_unit.sh
@@ -1,14 +1,20 @@
 #!/bin/bash
 
 pushd /srv/${PACKAGE}.git
 pushd tests
+
+set -x
 phpunit --debug ; retval=$?
+set - -x
 
 if [ ${retval} -ne 0 ]; then
-    echo "FAILED unit tests."
-    cat /srv/${PACKAGE}.git/logs/errors
+    echo "FAILED unit tests. Return code $?"
+    if [ -f "/srv/${PACKAGE}.git/logs/errors" ]; then
+        cat /srv/${PACKAGE}.git/logs/errors
+    fi
+
     exit 1
 fi
 
 popd
 popd