Add weakproxy test

Author: coolreader18

tests/snippets/weakrefs.py

@@ -1,4 +1,5 @@
-from _weakref import ref
+from _weakref import ref, proxy
+from testutils import assert_raises
 
 
 class X:
@@ -11,3 +12,17 @@ class X:
 assert callable(b)
 assert b() is a
 
+
+class G:
+    def __init__(self, h):
+        self.h = h
+
+
+g = G(5)
+p = proxy(g)
+
+assert p.h == 5
+
+del g
+
+assert_raises(ReferenceError, lambda: p.h)

vm/src/builtins.rs

@@ -751,6 +751,7 @@ pub fn make_module(vm: &VirtualMachine, module: PyObjectRef) {
         "NameError" => ctx.exceptions.name_error.clone(),
         "OverflowError" => ctx.exceptions.overflow_error.clone(),
         "RuntimeError" => ctx.exceptions.runtime_error.clone(),
+        "ReferenceError" => ctx.exceptions.reference_error.clone(),
         "NotImplementedError" => ctx.exceptions.not_implemented_error.clone(),
         "TypeError" => ctx.exceptions.type_error.clone(),
         "ValueError" => ctx.exceptions.value_error.clone(),