triggering error on required not set

tests/test_the_conf.py

@@ -39,3 +39,12 @@ def test_conf_from_obj(self):
         self.assertEqual('a', tc.option)
         tc.option = 1
         self.assertEqual('1', tc.option)
+
+    def test_trigger_error_w_required(self):
+        metaconf = {'parameters': [
+                        {'option': {'type': str, 'required': True}}],
+                    'config_files': []}
+        self.assertRaises(ValueError,
+                TheConf, metaconf, cmd_line_opts=[])
+        tc = TheConf(metaconf, cmd_line_opts=['--option=stuff'])
+        self.assertEqual('stuff', tc.option)

the_conf.example.yml

@@ -16,7 +16,7 @@ parameters:
   - nested:
     - value:
         type: int
-        required: true  # default
+        required: false  # default
     - other_value:
         type: bool
   - int_value:

the_conf/the_conf.py

@@ -66,6 +66,11 @@ def load(self):
             else:
                 raise Exception('unknown order %r')
 
+        for path, value, param in self._get_path_val_param():
+            if value is node.NoValue and param.get('required'):
+                raise ValueError('loading finished and %r is not set'
+                        % '.'.join(path))
+
     def write(self, config_file=None):
         if config_file is None and not self._config_files:
             raise ValueError('no config file to write in')