fix tests

astroquery/heasarc/core.py

@@ -154,10 +154,11 @@ def tables(self, *, master=False, keywords=None):
         `~astropy.table.Table` with columns: name, description
 
         """
-        if not isinstance(keywords, list):
-            keywords = [keywords]
-        if not all([isinstance(wrd, str) for wrd in keywords]):
-            raise ValueError('non-str found in keywords elements')
+        if keywords is not None:
+            if not isinstance(keywords, list):
+                keywords = [keywords]
+            if not all([isinstance(wrd, str) for wrd in keywords]):
+                raise ValueError('non-str found in keywords elements')
 
         # use 'mast' to include both 'master' and 'mastr'
         names, desc = [], []

astroquery/heasarc/tests/test_heasarc_remote.py

@@ -60,16 +60,16 @@
 @pytest.mark.remote_data
 class TestHeasarc:
 
-    def test_tap():
+    def test_tap(self):
         """Test Tap service"""
         assert Heasarc._tap is None
         tap = Heasarc.tap
         assert Heasarc._tap == tap
 
-    def test_meta():
+    def test_meta(self):
         """Test Meta service"""
         assert Heasarc._meta_info is None
-        Heasarc._meta()
+        Heasarc._meta
         assert Heasarc._meta_info is not None
 
     @pytest.mark.parametrize("coordinates", OBJ_LIST)