fix regression related to #21724

tester.py

@@ -60,11 +60,12 @@ class Tester():
         if '-h' in args:
             log('USAGE: ' + self.USAGE)
             sys.exit(0)
-        for index, arg in enumerate(args):
-            if arg not in self.VALID_ARGS and index + 1 != len(args):
-                log('Invalid argument given: "%s".\n' % arg)
-                log('USAGE: ' + self.USAGE)
-                sys.exit(1)
+        for arg in args:
+            if arg.startswith('-'):
+                if arg not in self.VALID_ARGS:
+                    log('Invalid argument given: "%s".\n' % arg)
+                    log('USAGE: ' + self.USAGE)
+                    sys.exit(1)
             else:
                 log("Optional target user : %s" % arg)
                 if not os.path.isdir(os.path.join('/home', arg)):