class_docstr: Test the Scene's handling of various dependencies.
class_docstr_tok: ["Test","the","Scene","'s","handling","of","various","dependencies","."]
docstr: Test the available datasets without a reader.
code: def test_available_dataset_no_readers(self):
      """Test the available datasets without a reader."""
      scene = Scene()
      pytest.raises(
          KeyError, scene.available_dataset_ids, reader_name="fake"
      )
      name_list = scene.available_dataset_ids()
      assert name_list == []
      # no sensors are loaded so we shouldn't get any comps either
      name_list = scene.available_dataset_ids(composites=True)
      assert name_list == []
  
imports: from unittest import mock
  import pytest
  import xarray
  from dask import array
  from satpy import Scene
  from satpy.tests.utils import make_cid, make_dataid, make_dsq, spy_decorator
label_desc: Use image node_id 3 for calling the TestSceneAllAvailableDatasets obj's underlying member method code with example usage: obj.test_available_dataset_no_readers() without return types