Add Iter of WeakProxy for test\test_weakref.py's "test_proxy_next"

Lib/test/test_weakref.py

@@ -432,8 +432,6 @@ class ReferencesTestCase(TestBase):
             # can be killed in the middle of the call
             "blech" in p
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_proxy_next(self):
         arr = [4, 5, 6]
         def iterator_func():

vm/src/builtins/weakproxy.rs

@@ -5,10 +5,10 @@ use crate::{
     atomic_func,
     class::PyClassImpl,
     function::{OptionalArg, PyComparisonValue, PySetterValue},
-    protocol::{PyMappingMethods, PySequenceMethods},
+    protocol::{PyIter, PyIterReturn, PyMappingMethods, PySequenceMethods},
     types::{
-        AsMapping, AsSequence, Comparable, Constructor, GetAttr, PyComparisonOp, Representable,
-        SetAttr,
+        AsMapping, AsSequence, Comparable, Constructor, GetAttr, IterNext, Iterable,
+        PyComparisonOp, Representable, SetAttr,
     },
     Context, Py, PyObject, PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine,
 };
@@ -71,7 +71,8 @@ crate::common::static_cell! {
     Comparable,
     AsSequence,
     AsMapping,
-    Representable
+    Representable,
+    IterNext
 ))]
 impl PyWeakProxy {
     fn try_upgrade(&self, vm: &VirtualMachine) -> PyResult {
@@ -122,6 +123,19 @@ impl PyWeakProxy {
         obj.del_item(&*needle, vm)
     }
 }
+impl Iterable for PyWeakProxy {
+    fn iter(zelf: PyRef<Self>, vm: &VirtualMachine) -> PyResult {
+        let obj = zelf.try_upgrade(vm)?;
+        Ok(obj.get_iter(vm)?.into())
+    }
+}
+
+impl IterNext for PyWeakProxy {
+    fn next(zelf: &Py<Self>, vm: &VirtualMachine) -> PyResult<PyIterReturn> {
+        let obj = zelf.try_upgrade(vm)?;
+        PyIter::new(obj).next(vm)
+    }
+}
 
 fn new_reference_error(vm: &VirtualMachine) -> PyRef<super::PyBaseException> {
     vm.new_exception_msg(