add tests for ForwardRef.hash

Author: andreas-h-sie

Lib/test/test_typing.py

@@ -2616,6 +2616,14 @@ def test_forward_equality(self):
         self.assertEqual(frm, typing.ForwardRef('int', module=__name__))
         self.assertNotEqual(frm, typing.ForwardRef('int', module='__other_name__'))
 
+    def test_forward_hash(self):
+        fr = typing.ForwardRef('int')
+        self.assertEqual(hash(fr), hash(typing.ForwardRef('int')))
+        self.assertNotEqual(hash(fr), hash(typing.ForwardRef('int', module=__name__)))
+        frm = typing.ForwardRef('int', module=__name__)
+        self.assertEqual(hash(frm), hash(typing.ForwardRef('int', module=__name__)))
+        self.assertNotEqual(hash(frm), hash(typing.ForwardRef('int', module='__other_name__')))
+
     def test_forward_equality_gth(self):
         c1 = typing.ForwardRef('C')
         c1_gth = typing.ForwardRef('C')