test: handle warnings generated by our own tests (#1469)

Our tests currently end with a very large list of warnings. This PR
fixes that:

* All of the Harness tests emit a `PendingDeprecationWarning` telling us
that Harness is going away and we should use Scenario. This seems like
something to simply ignore in our own tests, so I've added a `-W`
argument to Python to silence them in bulk.
* One `test_main` test raises a warning about controller storage going
away - there's another test that tests that warning happens, and the two
tests are otherwise identical. I've merged the two - we don't need them
both.
* Two of the secret tests check that `SecretInfo` objects can still be
created without providing the model UUID. I've added a `pytest.warns` to
(a) ensure that there's the warning, and (b) stop it appearing in the
tox output.
* Scenario should provide the model UUID when creating `SecretInfo`
objects. This is a one-line fix, so I've added it here - it stops
deprecation warnings, but is really more the code than the tests, but
since it's so small I think it's ok here.
* The `context.on` Scenario tests check that pre- and post- series
upgrade events work, and those raise warnings. I've split them off to a
separate test that verifies (and silences) the warning.

Fixes #1408

test/test_main.py

@@ -189,12 +189,6 @@ def test_storage_no_storage(self):
 
     def test_storage_with_storage(self):
         # here we patch juju_backend_available, so it gets set up and falls over when used
-        with patch('ops.storage.juju_backend_available') as juju_backend_available:
-            juju_backend_available.return_value = True
-            with pytest.raises(FileNotFoundError, match='state-get'):
-                self._check(ops.CharmBase, use_juju_for_storage=True)
-
-    def test_controller_storage_deprecated(self):
         with patch('ops.storage.juju_backend_available') as juju_backend_available:
             juju_backend_available.return_value = True
             with pytest.warns(DeprecationWarning, match='Controller storage'):

test/test_model.py

@@ -3643,11 +3643,13 @@ def test_from_dict(self):
         assert info.rotates is None
         assert info.description is None
 
-        info = ops.SecretInfo.from_dict('5', {'revision': 9})
+        with pytest.warns(DeprecationWarning, match='`model_uuid` should always be provided'):
+            info = ops.SecretInfo.from_dict('5', {'revision': 9})
         assert info.id == 'secret:5'
         assert info.revision == 9
 
-        info = ops.SecretInfo.from_dict('secret://abcd/6', {'revision': 9})
+        with pytest.warns(DeprecationWarning, match='`model_uuid` should always be provided'):
+            info = ops.SecretInfo.from_dict('secret://abcd/6', {'revision': 9})
         assert info.id == 'secret://abcd/6'
         assert info.revision == 9
 

testing/src/scenario/mocking.py

@@ -481,6 +481,7 @@ def secret_info_get(
             expires=secret.expire,
             rotation=secret.rotate,
             rotates=None,  # not implemented yet.
+            model_uuid=self._state.model.uuid,
         )
 
     def secret_set(

testing/tests/test_context_on.py

@@ -56,8 +56,6 @@ def _on_event(self, event: ops.EventBase):
         ("update_status", ops.UpdateStatusEvent),
         ("config_changed", ops.ConfigChangedEvent),
         ("upgrade_charm", ops.UpgradeCharmEvent),
-        ("pre_series_upgrade", ops.PreSeriesUpgradeEvent),
-        ("post_series_upgrade", ops.PostSeriesUpgradeEvent),
         ("leader_elected", ops.LeaderElectedEvent),
     ],
 )
@@ -72,6 +70,25 @@ def test_simple_events(event_name: str, event_kind: typing.Type[ops.EventBase]):
         assert isinstance(mgr.charm.observed[0], event_kind)
 
 
+@pytest.mark.parametrize(
+    "event_name, event_kind",
+    [
+        ("pre_series_upgrade", ops.PreSeriesUpgradeEvent),
+        ("post_series_upgrade", ops.PostSeriesUpgradeEvent),
+    ],
+)
+def test_simple_deprecated_events(event_name, event_kind):
+    ctx = scenario.Context(ContextCharm, meta=META, actions=ACTIONS)
+    # These look like:
+    #   ctx.run(ctx.on.pre_series_upgrade(), state)
+    with pytest.warns(DeprecationWarning):
+        with ctx(getattr(ctx.on, event_name)(), scenario.State()) as mgr:
+            mgr.run()
+            assert len(mgr.charm.observed) == 2
+            assert isinstance(mgr.charm.observed[1], ops.CollectStatusEvent)
+            assert isinstance(mgr.charm.observed[0], event_kind)
+
+
 @pytest.mark.parametrize("as_kwarg", [True, False])
 @pytest.mark.parametrize(
     "event_name,event_kind,owner",

tox.ini

@@ -104,7 +104,8 @@ deps =
     -e .
     -e testing
 commands =
-    pytest -n auto --ignore={[vars]tst_path}smoke -v --tb native {posargs}
+    pytest -n auto --ignore={[vars]tst_path}smoke -v --tb native \
+        -W 'ignore:Harness is deprecated:PendingDeprecationWarning' {posargs}
 
 [testenv:coverage]
 description = Run unit tests with coverage