code: def test_rgba_no_ndv(tiffs):
      with rasterio.open(str(tiffs.join("rgba_no_ndv.tif"))) as src:
          assert np.array_equal(src.dataset_mask(), alp)
  
file_path: rasterio/tests/test_dataset_mask.py
imports: from affine import Affine
  import numpy
  import pytest
  from affine import Affine
  import rasterio
  from rasterio.enums import Resampling
  from rasterio.errors import NodataShadowWarning
  from rasterio.crs import CRS
label_desc: Use image node_id 4 for calling a global function with example usage: test_rgba_no_ndv(tiffs) without return types