Make NDArrayType.__len__() a method, not a property

asdf-format · Apr 4, 2019 · 4b2e81e · 4b2e81e
1 parent 3e36570
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diff --git a/CHANGES.rst b/CHANGES.rst
@@ -5,6 +5,9 @@
 
 - Overhaul packaging infrastructure. Remove use of ``astropy_helpers``. [#670]
 
+- Fix bug in ``NDArrayType.__len__``.  It must be a method, not a
+  property. [#673]
+
 2.3.3 (2019-04-02)
 ------------------
 

diff --git a/asdf/tags/core/ndarray.py b/asdf/tags/core/ndarray.py
@@ -331,7 +331,6 @@ def dtype(self):
         else:
             return self._array.dtype
 
-    @property
     def __len__(self):
         if self._array is None:
             return self._shape[0]

diff --git a/asdf/tags/core/tests/test_ndarray.py b/asdf/tags/core/tests/test_ndarray.py
@@ -322,6 +322,17 @@ def check_asdf(asdf):
 
     helpers.assert_roundtrip_tree(tree, tmpdir, asdf_check_func=check_asdf)
 
+def test_len_roundtrip(tmpdir):
+    sequence = np.arange(0, 10, dtype=np.int)
+    tree = {
+        'sequence': sequence
+        }
+
+    def check_len(asdf):
+        s = asdf.tree["sequence"]
+        assert len(s) == 10
+
+    helpers.assert_roundtrip_tree(tree, tmpdir, asdf_check_func=check_len)
 
 def test_mask_arbitrary():
     content = """