examples/research_projects/rag-end2end-retriever/callbacks_rag.py/Seq2SeqLoggingCallback/on_test_end
class Seq2SeqLoggingCallback:    def on_test_end(self, trainer: pl.Trainer, pl_module: pl.LightningModule):
        save_json(pl_module.metrics, pl_module.metrics_save_path)
        return self._write_logs(trainer, pl_module, "test")