Files: Show error when listing dir contents fails in RemoteExplorer

Also, add test that checks that.

Author: ccordoba12

spyder/plugins/explorer/widgets/remote_explorer.py

@@ -681,9 +681,19 @@ async def _do_remote_upload_file(self, local_path):
 
     @AsyncDispatcher.QtSlot
     def _on_remote_ls(self, future):
-        # TODO: We should manage errors raised by _do_remote_ls
-        data = future.result()
-        self.set_files(data)
+        error = self._handle_future_response_error(
+            future,
+            _("List contents error"),
+            _("An error occured while trying to view a directory"),
+        )
+
+        if not error:
+            data = future.result()
+            self.set_files(data)
+        else:
+            # Set parent directory as root because the selected one can't be
+            # accessed
+            self.chdir(os.path.dirname(self.root_prefix[self.server_id]))
 
         if not self._operation_in_progress:
             self.sig_stop_spinner_requested.emit()

spyder/plugins/explorer/widgets/tests/test_remote_explorer.py

@@ -241,7 +241,9 @@ def test_copy_paste(
     treewidget.copy_action.triggered.emit()
 
     # Move to paste directory
-    treewidget.go_to_previous_directory()
+    with qtbot.waitSignal(treewidget.sig_stop_spinner_requested):
+        treewidget.go_to_previous_directory()
+
     qtbot.waitUntil(lambda: treewidget.model.rowCount() > 2)
 
     treewidget.chdir(copy_paste_dirs[1], server_id=remote_client_id)
@@ -519,6 +521,18 @@ def test_permission_errors(
     assert len(QMessageBox.critical.mock_calls) == 9
     assert treewidget.model.rowCount() == 1
 
+    # Try to move to directory that can't be read
+    with qtbot.waitSignal(treewidget.sig_stop_spinner_requested):
+        treewidget.go_to_previous_directory()
+
+    with qtbot.waitSignal(treewidget.sig_stop_spinner_requested):
+        treewidget.chdir(
+            f"/home/ubuntu/{dirname}/cant-read-dir", server_id=remote_client_id
+        )
+
+    assert len(QMessageBox.critical.mock_calls) == 10
+    assert treewidget.model.rowCount() == 3
+
 
 if __name__ == "__main__":
     pytest.main()