def test_dataloaders(self) -> Optional[EVAL_DATALOADERS]:
        """The test dataloader(s) used during ``trainer.test()``."""
        if (combined_loader := self.test_loop._combined_loader) is not None:
            return combined_loader.iterables
        return None
The test dataloader(s) used during ``trainer.test()``.
src/lightning/pytorch/trainer/trainer.py