allow extra **kwargs in @deferred_performer-wrapped functions

Author: radix

txeffect/__init__.py

@@ -66,11 +66,11 @@ def perform_foo(dispatcher, foo):
             return do_side_effecting_deferred_operation(foo)
     """
     @wraps(f)
-    def deferred_wrapper(*args):
+    def deferred_wrapper(*args, **kwargs):
         box = args[-1]
         pass_args = args[:-1]
         try:
-            result = f(*pass_args)
+            result = f(*pass_args, **kwargs)
         except:
             box.fail(sys.exc_info())
         else:

txeffect/test_txeffect.py

@@ -210,6 +210,16 @@ def original(something, dispatcher, intent):
         wrapped = deferred_performer(new_func)
         self.assertEqual(wrapped.__name__, 'deferred_wrapper')
 
+    def test_kwargs(self):
+        """Additional kwargs are passed through."""
+        @deferred_performer
+        def p(dispatcher, intent, extra):
+            return extra
+
+        dispatcher = lambda _: partial(p, extra='extra val')
+        result = self.successResultOf(perform(dispatcher, Effect('foo')))
+        self.assertEqual(result, 'extra val')
+
 
 class ExcInfoToFailureTests(TestCase):
     """Tests for :func:`exc_info_to_failure`."""