Add test to demonstrate the filter for asdf file reads

gwcs/examples.py

@@ -73,6 +73,17 @@ def gwcs_2d_shift_scale():
     pipe = [(DETECTOR_2D_FRAME, m3), (ICRC_SKY_FRAME, None)]
     return wcs.WCS(pipe)
 
+def gwcs_2d_bad_bounding_box_order():
+    m1 = models.Shift(1) & models.Shift(2)
+    m2 = models.Scale(5) & models.Scale(10)
+    m3 = m1 | m2
+
+    # Purposefully set the bounding box in the wrong order
+    m3.bounding_box = ((1, 2), (3, 4))
+
+    pipe = [(DETECTOR_2D_FRAME, m3), (ICRC_SKY_FRAME, None)]
+    return wcs.WCS(pipe)
+
 
 def gwcs_1d_freq_quantity():
 

gwcs/tests/test_wcs.py

@@ -25,6 +25,7 @@
 from ..utils import CoordinateFrameError
 from .utils import _gwcs_from_hst_fits_wcs
 from . import data
+from ..examples import gwcs_2d_bad_bounding_box_order
 
 
 data_path = os.path.split(os.path.abspath(data.__file__))[0]
@@ -1443,3 +1444,29 @@ def test_bounding_box_is_returned_F():
 
     # Show the the bounding box is different between the two WCS objects
     assert gwcs_object_after.bounding_box != gwcs_object_before.bounding_box
+
+
+def test_no_bounding_box_if_read_from_file(tmp_path):
+    bad_wcs = gwcs_2d_bad_bounding_box_order()
+
+    # Check the waring is issued for the bounding box of this WCS object
+    with pytest.warns(wcs.GwcsBoundingBoxWarning):
+        bad_wcs.bounding_box
+
+    # Check that the warning is not issued again the second time
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        bad_wcs.bounding_box
+
+    # Write a bad wcs bounding box to an asdf file
+    asdf_file = tmp_path / "bad_wcs.asdf"
+    af = asdf.AsdfFile({"wcs": gwcs_2d_bad_bounding_box_order()}) # re-create the bad wcs object
+    af.write_to(asdf_file)
+
+    with asdf.open(asdf_file) as af:
+        wcs_from_file = af["wcs"]
+
+    # Check that no warning is issued for the bounding box of this WCS object
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        wcs_from_file.bounding_box