Add test for duplicate data when resaving model to fits (#7358)

* Add test for duplicate data when resaving model to fits

When resaving a model to fits, asdf loses track of array-hdu
links and saves arrays in both hdu and as internal blocks in the
asdf tree. This can make an asdf tree that is larger than what
can be stored in a fits hdu.

See asdf issue: asdf-format/asdf#1232

This test is skipped as it fails with the current asdf version.

modify imports and use context manager for test_fits

Co-authored-by: James Davies <[email protected]>

use context manager in test_fits

Co-authored-by: James Davies <[email protected]>

improve test docstring in test_fits

* bump asdf version to 2.14.1 to fix hdu data

unskip test for issue #7354

fixes #7354

jwst/datamodels/tests/test_fits.py

@@ -4,7 +4,8 @@
 import numpy as np
 import pytest
 
-from jwst.datamodels import JwstDataModel, RampModel
+from jwst import datamodels
+from jwst.datamodels import ImageModel, JwstDataModel, RampModel
 
 
 @pytest.fixture
@@ -68,3 +69,25 @@ def test_casting():
         total = dm.data.sum()
         dm.data = dm.data + 2
         assert dm.data.sum() > total
+
+
+def test_resave_duplication_bug(tmp_path):
+    """
+    An issue in asdf (https://github.com/asdf-format/asdf/issues/1232)
+    resulted in duplication of data when a model was read from and then
+    written to a fits file. A resave results in array data being written to
+    both hdus and as internal blocks within the asdf tree (which is then
+    stored in the asdf hdu).
+    """
+    fn1 = tmp_path / "test1.fits"
+    fn2 = tmp_path / "test2.fits"
+
+    arr = np.zeros((1000, 100), dtype='f4')
+    m = ImageModel(arr)
+    m.save(fn1)
+
+    with datamodels.open(fn1) as m2:
+        m2.save(fn2)
+
+    with fits.open(fn1) as ff1, fits.open(fn2) as ff2:
+        assert ff1['ASDF'].size == ff2['ASDF'].size

setup.cfg

@@ -27,7 +27,7 @@ python_requires = >=3.8
 setup_requires =
     setuptools_scm
 install_requires =
-    asdf>=2.13.0
+    asdf>=2.14.1
     asdf-transform-schemas>=0.3.0
     astropy>=5.1
     BayesicFitting>=3.0.1