class_docstr: Test the Scene's handling of various dependencies.
class_docstr_tok: ["Test","the","Scene","'s","handling","of","various","dependencies","."]
docstr: Test available_composite_ids when some datasets aren't available.
code: def test_available_composites_known_versus_all(self):
      """Test available_composite_ids when some datasets aren't available."""
      scene = Scene(
          filenames=["fake1_1.txt"],
          reader="fake1",
          reader_kwargs={"not_available": ["ds2", "ds3"]},
      )
      all_comps = scene.all_composite_names()
      avail_comps = scene.available_composite_names()
      # there should always be more known composites than available composites
      assert len(all_comps) > len(avail_comps)
      for not_avail_comp in ("comp2", "comp3"):
          assert not_avail_comp in all_comps
          assert not_avail_comp not in avail_comps
  
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 9 for calling the TestSceneAllAvailableDatasets obj's underlying member method code with example usage: obj.test_available_composites_known_versus_all() without return types