The __round__ hook didn't accept ndigits argument.

docs/changes.rst

@@ -27,6 +27,8 @@ Note that version 1.17.0 drops support for Python 3.6 and 3.7. Python version
   when instead it should have been called directly, ignoring that binding was
   not possible. 
 
+* The `__round__` hook for the object proxy didn't accept `ndigits` argument.
+
 Version 1.16.0
 --------------
 

src/wrapt/_wrappers.c

@@ -1318,26 +1318,34 @@ static PyObject *WraptObjectProxy_reversed(
 
 #if PY_MAJOR_VERSION >= 3
 static PyObject *WraptObjectProxy_round(
-        WraptObjectProxyObject *self, PyObject *args)
+        WraptObjectProxyObject *self, PyObject *args, PyObject *kwds)
 {
+    PyObject *ndigits = NULL;
+
     PyObject *module = NULL;
     PyObject *dict = NULL;
     PyObject *round = NULL;
 
     PyObject *result = NULL;
 
+    char *const kwlist[] = { "ndigits", NULL };
+
     if (!self->wrapped) {
       PyErr_SetString(PyExc_ValueError, "wrapper has not been initialized");
       return NULL;
     }
 
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|O:ObjectProxy",
+        kwlist, &ndigits)) {
+        return NULL;
+    }
+
     module = PyImport_ImportModule("builtins");
 
     if (!module)
         return NULL;
 
-    dict = PyModule_GetDict(module);
-    round = PyDict_GetItemString(dict, "round");
+    round = PyObject_GetAttrString(module, "round");
 
     if (!round) {
         Py_DECREF(module);
@@ -1347,7 +1355,7 @@ static PyObject *WraptObjectProxy_round(
     Py_INCREF(round);
     Py_DECREF(module);
 
-    result = PyObject_CallFunctionObjArgs(round, self->wrapped, NULL);
+    result = PyObject_CallFunctionObjArgs(round, self->wrapped, ndigits, NULL);
 
     Py_DECREF(round);
 
@@ -1818,7 +1826,8 @@ static PyMethodDef WraptObjectProxy_methods[] = {
     { "__format__",  (PyCFunction)WraptObjectProxy_format, METH_VARARGS, 0 },
     { "__reversed__", (PyCFunction)WraptObjectProxy_reversed, METH_NOARGS, 0 },
 #if PY_MAJOR_VERSION >= 3
-    { "__round__",  (PyCFunction)WraptObjectProxy_round, METH_NOARGS, 0 },
+    { "__round__",  (PyCFunction)WraptObjectProxy_round,
+                    METH_VARARGS | METH_KEYWORDS, 0 },
 #endif
     { "__complex__",  (PyCFunction)WraptObjectProxy_complex, METH_NOARGS, 0 },
 #if PY_MAJOR_VERSION > 3 || (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 7)

src/wrapt/wrappers.py

@@ -133,8 +133,8 @@ def __reversed__(self):
         return reversed(self.__wrapped__)
 
     if not PY2:
-        def __round__(self):
-            return round(self.__wrapped__)
+        def __round__(self, ndigits=None):
+            return round(self.__wrapped__, ndigits)
 
     if sys.hexversion >= 0x03070000:
         def __mro_entries__(self, bases):

tests/test_object_proxy.py

@@ -1852,7 +1852,9 @@ def test_fractions_round(self):
         proxy = wrapt.ObjectProxy(instance)
 
         self.assertEqual(round(instance), round(proxy))
-
+        self.assertEqual(round(instance, 3), round(proxy, 3))
+        self.assertEqual(round(instance, ndigits=3), round(proxy, ndigits=3))
+
 class TestArgumentUnpacking(unittest.TestCase):
 
     def test_self_keyword_argument_on_dict(self):