io.text_encoding return utf-8 for RustPython for now

Lib/test/test_pathlib.py

@@ -1535,8 +1535,6 @@ class _BasePathTest(object):
         self.assertIs(False, P(BASE + '\udfff').exists())
         self.assertIs(False, P(BASE + '\x00').exists())
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_open_common(self):
         p = self.cls(BASE)
         with (p / 'fileA').open('r') as f:
@@ -1566,8 +1564,6 @@ class _BasePathTest(object):
         self.assertRaises(TypeError, (p / 'fileA').write_text, b'somebytes')
         self.assertEqual((p / 'fileA').read_text(encoding='latin-1'), 'äbcdefg')
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_write_text_with_newlines(self):
         p = self.cls(BASE)
         # Check that `\n` character change nothing

vm/src/stdlib/io.rs

@@ -3676,7 +3676,8 @@ mod _io {
         vm: &VirtualMachine,
     ) -> PyResult<PyStrRef> {
         if vm.is_none(&encoding) {
-            return Ok(vm.ctx.new_str("locale"));
+            // TODO: This is `locale` encoding - but we don't have locale encoding yet
+            return Ok(vm.ctx.new_str("utf-8"));
         }
         encoding.try_into_value(vm)
     }