code: def testCreateAtlasIfNoSizeSpecified(self):
      # Verify that manifests and atlases contains single items.
      # and verify atlas size is correct.
      atlas_settings = montage.SpriteAtlasSettings(img_format="png")
      source_images_with_statuses = [
          (Image.new("RGBA", (50, 30)), "")
      ] * 20
      source_paths = [
          "/some/path/file" + str(i) + ".jpg" for i in range(0, 20)
      ]
  
      atlas_generator = montage.SpriteAtlasGenerator(
          images_with_statuses=source_images_with_statuses,
          img_src_paths=source_paths,
          atlas_settings=atlas_settings,
          default_img=Image.new("RGBA", (50, 30)),
      )
      atlases, manifests = atlas_generator.create_atlas()
  
      self.assertEqual(len(atlases), 1)
      self.assertEqual(atlases[0].size, (250, 150))
      self.assertEqual(len(manifests), 1)
      self.assertEqual(len(manifests[0]), 20)
  
file_path: facets/facets_atlasmaker/montage_test.py
imports: from absl.testing import absltest
  from PIL import Image
  from PIL import ImageColor
  import montage
label_desc: Use image node_id 4 for calling the SpriteAtlasGeneratorTests obj's underlying member method code with example usage: obj.testCreateAtlasIfNoSizeSpecified() without return types