add a remote regression test

remove unused variable

add remote test and restructure fallback

catch warning

import warnings

try changing the warning filter to 'always'

check in message, not in str

rearrange warning test

DEBUG

reading the instructions tells you how to use the tool.

fix to use pytest.warns

Author: keflavich

astroquery/heasarc/core.py

@@ -262,6 +262,10 @@ def _parse_result(self, response, verbose=False):
             warnings.warn(NoResultsWarning("No matching rows were found in the query."))
             return Table()
 
+        if "XTENSION= 'IMAGE   '" in response.text:
+            data = BytesIO(response.content)
+            return self._blank_table_fallback(data)
+
         try:
             data = BytesIO(response.content)
             return Table_read(data, hdu=1)
@@ -270,8 +274,6 @@ def _parse_result(self, response, verbose=False):
                 return self._fallback(response.text)
             except Exception:
                 return self._old_w3query_fallback(response.content)
-        except AttributeError:
-            return self._blank_table_fallback(data)
 
 
     def _args_to_payload(self, **kwargs):

astroquery/heasarc/tests/data/be6d5c35.dat

@@ -0,0 +1 @@
+SIMPLE  =                    T / Browse (FitsDisplay V0.2)                      BITPIX  =                    8                                                  NAXIS   =                    0 / Dummy HDU                                      EXTEND  =                    T / Extensions allowed                             END                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             XTENSION= 'IMAGE   '           / Tables not returning data                      BITPIX  =                    8                                                  NAXIS   =                    0                                                  PCOUNT  =                    0                                                  GCOUNT  =                    1                                                                                                                                  COMMENT    heasarc_fermilpsc : No matching rows                                 END                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             

astroquery/heasarc/tests/test_heasarc_remote.py

@@ -2,11 +2,17 @@
 
 import pytest
 import requests
+import warnings
 
 from ...heasarc import Heasarc
 
 from .conftest import MockResponse, parametrization_local_save_remote, skycoord_3C_273
 
+from astroquery.exceptions import NoResultsWarning
+
+from astropy.coordinates import SkyCoord
+from astropy import units as u
+
 
 @parametrization_local_save_remote
 class TestHeasarc:
@@ -96,3 +102,18 @@ def test_query_region(self):
             skycoord_3C_273, mission=mission, radius="1 degree")
 
         assert len(table) == 63
+
+    def test_query_region_nohits(self):
+        """
+        Regression test for #2560: HEASARC returns a FITS file as a null result
+        """
+        heasarc = Heasarc()
+
+        with warnings.catch_warnings(record=True) as warn:
+        with pytest.warns(NoResultsWarning, match='No matching rows were found in the query.'):
+            table = heasarc.query_region(
+                    SkyCoord(0.28136*u.deg, -0.09789*u.deg, frame='fk5'),
+                    mission='fermilpsc', radius=0.1*u.deg)
+
+        assert len(table) == 0
+        assert 'heasarc_fermigbrst' in table.meta['COMMENT'][0]