Have config verify that at least one helper is enabled

sbws/lib/helperrelay.py

@@ -48,6 +48,7 @@ class HelperRelayList:
             self.controller = c
         else:
             self.controller = controller
+        assert len(helpers) > 0
         for helper in helpers:
             assert isinstance(helper, HelperRelay)
         self._socks_proxy = (conf['tor']['socks_host'],

sbws/util/config.py

@@ -258,6 +258,9 @@ def _validate_helpers(conf):
         assert valid
         if section.getboolean(key):
             addtional_helper_sections.append('{}.{}'.format(sec, key))
+    if len(addtional_helper_sections) < 1:
+        errors.append('Need more than 0 enabled helpers in [{}] section'
+                      .format(sec))
     fps = {
         'relay': {},
     }