Various improvements

tests/test_update_pkg.py

@@ -155,6 +155,25 @@ class TestFetchTodoListErrors:
             with pytest.raises(debian_todo.PackageUpdateError) as exc_info:
                 debian_todo.fetch_todo_list()
             assert "Invalid JSON" in str(exc_info.value)
+            assert "not valid json {" in str(exc_info.value)
+
+    def test_udd_high_load_html_response(self):
+        """Test known UDD overload HTML response handling."""
+        with patch("debian_todo.urlopen") as mock_urlopen:
+            mock_response = MagicMock()
+            mock_response.read.return_value = (
+                b"<p><b>Current system load (26.1) is too high. "
+                b"Please retry later!</b></p>\n"
+            )
+            mock_response.__enter__ = lambda self: self
+            mock_response.__exit__ = lambda self, *args: None
+            mock_urlopen.return_value = mock_response
+
+            with pytest.raises(debian_todo.PackageUpdateError) as exc_info:
+                debian_todo.fetch_todo_list()
+
+            assert "temporary overload page" in str(exc_info.value)
+            assert "Please retry later" in str(exc_info.value)
 
     def test_successful_fetch(self):
         """Test successful fetch."""