diff --git a/tools/commands.js b/tools/commands.js
index be48b08a9d..d801d99abe 100644
--- a/tools/commands.js
+++ b/tools/commands.js
@@ -1163,6 +1163,8 @@ main.registerCommand({
   var testPackages = null;
   try {
     var packages = getPackagesForTest(options.args);
+    if (typeof packages === "number")
+      return packages;
     testPackages = packages.testPackages;
     localPackages = packages.localPackages;
     options.localPackageNames = packages.localPackages;