Merge pull request #1837 from nandita11/sha-value_error

Add NoResultWarning for empty table in sha

Author: bsipocz

CHANGES.rst

@@ -78,6 +78,9 @@ sha
 
 - Change URL to https. [#2108]
 
+- A ``NoResultsWarning`` is now returned when there is return of any empty
+  table. [#1837]
+
 
 Infrastructure, Utility and Other Changes and Additions
 -------------------------------------------------------

astroquery/sha/core.py

@@ -3,10 +3,11 @@
 import os
 import io
 import requests
+import warnings
 import numpy as np
 from astropy.table import Table
 import astropy.io.fits as fits
-
+from ..exceptions import NoResultsWarning
 
 __all__ = ['query', 'save_file', 'get_file']
 id_parse = re.compile(r'ID\=(\d+)')
@@ -144,7 +145,12 @@ def parse_line(line, cs=cs):
     dtypes = _map_dtypes(type_names, field_widths)
     # To table
     # transpose data for appropriate table instance handling
-    table = Table(list(zip(*data)), names=col_names, dtype=dtypes)
+
+    if len(data) > 0:
+        table = Table(list(zip(*data)), names=col_names, dtype=dtypes)
+    else:
+        warnings.warn(NoResultsWarning("No matching rows were found in the query."))
+        table = Table()
     return table
 
 

astroquery/sha/tests/test_sha_remote.py

@@ -0,0 +1,16 @@
+import pytest
+
+from astropy.table import Table
+
+from astroquery import sha
+from astroquery.exceptions import NoResultsWarning
+
+
+@pytest.mark.remote_data
+def test_query_no_results():
+    # Test for issue #1836
+    with pytest.warns(NoResultsWarning):
+        result = sha.query(ra=219.57741, dec=64.171525, size=0.001)
+
+    assert isinstance(result, Table)
+    assert len(result) == 0