Add update-status itest (#66)

lib/charms/alertmanager_k8s/v0/alertmanager_dispatch.py

@@ -279,7 +279,12 @@ def update_relation_data(self, event: RelationEvent = None):
             # a single consumer charm's unit may be related to multiple providers
             if self.name in self.charm.model.relations:
                 for relation in self.charm.model.relations[self.name]:
+                    # Sometimes (e.g. when an app is removed with `--force`), there is a dangling
+                    # relation, for which we get the following error:
+                    # ops.model.ModelError: b'ERROR relation 17 not found (not found)\n'
+                    # when trying to `network-get alerting`.
                     relation.data[self.charm.unit].update(self._generate_relation_data(relation))
+
         else:
             # update relation data only for the newly joined relation
             event.relation.data[self.charm.unit].update(

tests/integration/test_update_status_pressure.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+# Copyright 2021 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+"""This test module tests common lifecycle behaviors under frequent update-status hook firing.
+
+0. Set update-status frequency to the minimum possible
+1. Deploys and relate the charm-under-test
+2. Remove related app(s)
+"""
+
+import asyncio
+import logging
+from pathlib import Path
+
+import pytest
+import yaml
+from helpers import is_alertmanager_up
+from pytest_operator.plugin import OpsTest
+
+logger = logging.getLogger(__name__)
+
+METADATA = yaml.safe_load(Path("./metadata.yaml").read_text())
+app_name = METADATA["name"]
+resources = {"alertmanager-image": METADATA["resources"]["alertmanager-image"]["upstream-source"]}
+
+
+@pytest.mark.abort_on_fail
+async def test_setup_env(ops_test: OpsTest):
+    await ops_test.model.set_config(
+        {"update-status-hook-interval": "10s", "logging-config": "<root>=WARNING; unit=DEBUG"}
+    )
+
+
+@pytest.mark.abort_on_fail
+async def test_deploy_multiple_units(ops_test: OpsTest, charm_under_test):
+    """Deploy the charm-under-test."""
+    logger.info("build charm from local source folder")
+
+    logger.info("deploy charms")
+    await asyncio.gather(
+        ops_test.model.deploy(
+            charm_under_test, application_name=app_name, resources=resources, num_units=2
+        ),
+        ops_test.model.deploy("ch:prometheus-k8s", application_name="prom", channel="edge"),
+    )
+
+    await asyncio.gather(
+        ops_test.model.add_relation(app_name, "prom"),
+        ops_test.model.wait_for_idle(status="active", timeout=300),
+    )
+
+    assert await is_alertmanager_up(ops_test, app_name)
+
+
+@pytest.mark.abort_on_fail
+async def test_remove_related_app(ops_test: OpsTest):
+    await ops_test.model.applications["prom"].remove()
+    # Block until it is really gone. Added after an itest failed when tried to redeploy:
+    # juju.errors.JujuError: ['cannot add application "related-app": application already exists']
+    await ops_test.model.block_until(lambda: "prom" not in ops_test.model.applications)
+    await ops_test.model.wait_for_idle(apps=[app_name], status="active", timeout=300)
+    assert await is_alertmanager_up(ops_test, app_name)
+
+
+@pytest.mark.abort_on_fail
+async def test_wait_through_a_few_update_status_cycles(ops_test: OpsTest):
+    await asyncio.sleep(60)  # should be longer than the update-status period
+
+    # "Disable" update-status so the charm gets a chance to become idle for long enough for
+    # wait_for_idle to succeed
+    await ops_test.model.set_config({"update-status-hook-interval": "60m"})
+
+    await ops_test.model.wait_for_idle(apps=[app_name], status="active", timeout=300)

tox.ini

@@ -100,10 +100,10 @@ commands =
 description = Run integration tests
 deps =
     #git+https://github.com/juju/python-libjuju.git
-    juju
+    juju==2.9.7
     pytest
     #git+https://github.com/charmed-kubernetes/pytest-operator.git
-    pytest-operator
+    pytest-operator==0.15.0
 commands =
     pytest -v --tb native --log-cli-level=INFO -s {posargs} {toxinidir}/tests/integration