Making tests using the messenger vocabulary non-remote.

The messenger_vocabulary fixture should have made them non-remote, but
I've never actually tested that.  It now turns out that astropy.data doesn't
use requests and hence my nice requests mocker just didn't work.

I've now replaced it by code seeding astropy.data's cache.  This is a
pattern we ought to use whenever code uses IVOA vocabularies.  I wonder
where we should document this?

pyvo/registry/regtap.py

@@ -520,7 +520,7 @@ def standard_id(self):
 
     def access_modes(self):
         """
-        returns a list of interface identifiers available on
+        returns a set of interface identifiers available on
         this resource.
 
         For standard interfaces, get_service will return a service

pyvo/registry/tests/test_regtap.py

@@ -20,6 +20,8 @@
 
 from astropy.utils.data import get_pkg_data_contents
 
+from .commonfixtures import messenger_vocabulary
+
 
 get_pkg_data_contents = partial(
     get_pkg_data_contents, package=__package__, encoding='binary')
@@ -274,8 +276,10 @@ def test_servicetype():
     regsearch(servicetype='table')
 
 
-@pytest.mark.remote_data
-@pytest.mark.usefixtures('waveband_fixture', 'capabilities')
+@pytest.mark.usefixtures(
+    'waveband_fixture', 
+    'capabilities', 
+    'messenger_vocabulary')
 def test_waveband():
     regsearch(waveband='optical')
 

pyvo/registry/tests/test_rtcons.py

@@ -16,16 +16,7 @@
 from pyvo.registry import rtcons
 from pyvo.dal import query as dalq
 
-
-@pytest.fixture()
-def messenger_vocabulary(mocker):
-    def callback(request, context):
-        return get_pkg_data_contents('data/messenger.desise')
-
-    with mocker.register_uri(
-        'GET', 'http://www.ivoa.net/rdf/messenger', content=callback
-    ) as matcher:
-        yield matcher
+from .commonfixtures import messenger_vocabulary
 
 
 class TestAbstractConstraint:
@@ -128,7 +119,6 @@ def test_legacy_term(self):
 
 
 @pytest.mark.usefixtures('messenger_vocabulary')
-@pytest.mark.remote_data
 class TestWavebandConstraint:
     def test_basic(self):
         assert (rtcons.Waveband("Infrared", "EUV").get_search_condition()
@@ -301,23 +291,23 @@ def where_clause_for(*args, **kwargs):
         return rtcons.build_regtap_query(cons
             ).split("\nWHERE\n", 1)[1].split("\nGROUP BY\n")[0]
 
-    @pytest.mark.remote_data
+    @pytest.mark.usefixtures('messenger_vocabulary')
     def test_from_constraints(self):
         assert self.where_clause_for(
             rtcons.Waveband("EUV"),
             rtcons.Author("%Hubble%")
             ) == ("(1 = ivo_hashlist_has(rr.resource.waveband, 'euv'))\n"
                 "  AND (role_name LIKE '%Hubble%' AND base_role='creator')")
 
-    @pytest.mark.remote_data
+    @pytest.mark.usefixtures('messenger_vocabulary')
     def test_from_keywords(self):
         assert self.where_clause_for(
             waveband="EUV",
             author="%Hubble%"
             ) == ("(1 = ivo_hashlist_has(rr.resource.waveband, 'euv'))\n"
                 "  AND (role_name LIKE '%Hubble%' AND base_role='creator')")
 
-    @pytest.mark.remote_data
+    @pytest.mark.usefixtures('messenger_vocabulary')
     def test_mixed(self):
         assert self.where_clause_for(
             rtcons.Waveband("EUV"),