Add a unit test for asMaskedImage

tests/test_coadds.py

@@ -21,6 +21,7 @@
 
 import unittest
 from collections.abc import Iterable, Mapping
+from itertools import product
 
 import lsst.cell_coadds.test_utils as test_utils
 import lsst.geom as geom
@@ -326,6 +327,19 @@ def test_exploded_psf_image(self):
                 geom.Extent2I(self.nx * self.outer_size_x, self.ny * self.outer_size_y),
             )
 
+    def test_asMaskedImage(self):
+        """Test the asMaskedImage method for an ExplodedCoadd object."""
+        masked_image = self.exploded_coadd.asMaskedImage()
+        masked_image.setXY0(self.multiple_cell_coadd.outer_bbox.getMin())
+        base_bbox = self.multiple_cell_coadd.grid.bbox_of(Index2D(0, 0)).dilatedBy(self.border_size)
+        for (cell_x, cell_y) in product(range(self.nx), range(self.ny)):
+            bbox = base_bbox.shiftedBy(geom.Extent2I(cell_x * self.outer_size_x, cell_y * self.outer_size_y))
+            with self.subTest(cell_x=cell_x, cell_y=cell_y):
+                self.assertMaskedImagesEqual(
+                    masked_image[bbox],
+                    self.multiple_cell_coadd.cells[Index2D(cell_x, cell_y)].outer.asMaskedImage(),
+                )
+
 
 class StitchedCoaddTestCase(BaseMultipleCellCoaddTestCase):
     """Test the construction and methods of a StitchedCoadd instance."""