Merge pull request #1921 from nataliekorzh/empty-obs

Added case for catching empty observations product requests

Author: C. E. Brasseur

CHANGES.rst

@@ -41,6 +41,8 @@ mast
   ``Core.get_token()``, ``Core.enable_s3_hst_dataset()``, ``Core.disable_s3_hst_dataset()`` and 
   variables obstype and silent [#1884]
 - Added Zcut functionality to astroquery [#1911]
+- Fixed error causing empty products passed to ``Observations.get_product_list()`` to yeild a
+  non-empty result. [#1921]
 
 esa/hubble
 ^^^^^^^^^^

astroquery/mast/observations.py

@@ -427,6 +427,8 @@ def get_product_list_async(self, observations):
         -------
             response : list of `~requests.Response`
         """
+        if len(observations) == 0 or not observations["obsid"]:
+            raise InvalidQueryError("Observation list is empty, no associated products.")
 
         # getting the obsid list
         if isinstance(observations, Row):