class_docstr: Image dataset for test split of `Cityscapes dataset`_.
  
  .. _`Cityscapes dataset`: https://www.cityscapes-dataset.com
  
  .. note::
  
      Please manually download the data because it is not allowed to
      re-distribute Cityscapes dataset.
  
  Args:
      data_dir (string): Path to the dataset directory. The directory should
          contain the :obj:`leftImg8bit` directory. If :obj:`auto` is given,
          it uses :obj:`$CHAINER_DATSET_ROOT/pfnet/chainercv/cityscapes` by
          default.
  
  This dataset returns the following data.
  
  .. csv-table::
      :header: name, shape, dtype, format
  
      :obj:`img`, ":math:`(3, H, W)`", :obj:`float32`,         "RGB, :math:`[0, 255]`"
code: def __init__(self, data_dir="auto"):
      super(CityscapesTestImageDataset, self).__init__()
  
      if data_dir == "auto":
          data_dir = download.get_dataset_directory(
              "pfnet/chainercv/cityscapes"
          )
  
      img_dir = os.path.join(
          data_dir, os.path.join("leftImg8bit", "test")
      )
      if not os.path.exists(img_dir):
          raise ValueError(
              "Cityscapes dataset does not exist at the expected location."
              "Please download it from https://www.cityscapes-dataset.com/."
              "Then place directory leftImg8bit at {}.".format(
                  os.path.join(data_dir, "leftImg8bit")
              )
          )
  
      self.img_paths = []
      for city_dname in sorted(glob.glob(os.path.join(img_dir, "*"))):
          for img_path in sorted(
              glob.glob(os.path.join(city_dname, "*_leftImg8bit.png"))
          ):
              self.img_paths.append(img_path)
  
      self.add_getter("img", self._get_image)
      self.keys = "img"
  
file_path: chainercv/chainercv/datasets/cityscapes/cityscapes_test_image_dataset.py
imports: import glob
  import os
  from chainer.dataset import download
  from chainercv.chainer_experimental.datasets.sliceable import GetterDataset
  from chainercv.utils import read_image
label_desc: Use image node_id 1 to create a new CityscapesTestImageDataset object from inherited base classes: GetterDataset with example: obj = CityscapesTestImageDataset(data_dir)