cannot add unvalaible consistency for an option

test/test_option_consistency.py

@@ -20,6 +20,13 @@ def test_consistency():
     raises(ConfigError, "a.impl_add_consistency('not_equal', 'a')")
 
 
+def test_consistency_not_exists():
+    a = IntOption('a', '')
+    b = IntOption('b', '')
+    od = OptionDescription('od', '', [a, b])
+    raises(ConfigError, "a.impl_add_consistency('not_exists', b)")
+
+
 def test_consistency_warnings_only():
     a = IntOption('a', '')
     b = IntOption('b', '')

tiramisu/i18n.py

@@ -49,5 +49,4 @@ gettext.translation(APP_NAME, fallback=True)
 
 t = gettext.translation(APP_NAME, fallback=True)
 
-def _(msg):
-    return t.gettext(msg)
+_ = t.gettext

tiramisu/option/baseoption.py

@@ -147,7 +147,7 @@ class Base(StorageBase):
                                    self.impl_getname()))
         if self.impl_get_callback()[0] is not None:
             raise ConfigError(_("a callback is already set for option {0}, "
-                                "cannot set another one's".format(self.impl_getname())))
+                                "cannot set another one's").format(self.impl_getname()))
         self._validate_callback(callback, callback_params)
         if callback is not None:
             validate_callback(callback, callback_params, 'callback')
@@ -629,7 +629,7 @@ class Option(OnlyOption):
         :param params: extra params (only warnings_only are allowed)
         """
         if self.impl_is_readonly():  # pragma: optional cover
-            raise AttributeError(_("'{0}' ({1}) cannont add consistency, option is"
+            raise AttributeError(_("'{0}' ({1}) cannot add consistency, option is"
                                    " read-only").format(
                                        self.__class__.__name__,
                                        self.impl_getname()))
@@ -658,6 +658,8 @@ class Option(OnlyOption):
                 raise ConfigError(_('every options in consistency must be '
                                     'multi or none'))
         func = '_cons_{0}'.format(func)
+        if func not in dir(self):
+            raise ConfigError(_('consistency {0} not available for this option'))
         all_cons_opts = tuple([self] + list(other_opts))
         value = self.impl_getdefault()
         if value is not None: