Added a very basic smoke test. Run it with tox -e smoke

.gitignore

@@ -11,3 +11,8 @@ venv
 .vscode
 .coverage
 /.tox
+
+# Smoke test artifacts
+*.tar.gz
+*.charm
+test/charms/test_smoke/requirements.txt

test/charms/test_smoke/README.md

@@ -0,0 +1,9 @@
+# smoke
+
+## Description
+
+A simple test charm for running smoke tests.
+
+## Usage
+
+Run `tox -e smoke` in the root directory of this repository to build and deploy this charm.

test/charms/test_smoke/charmcraft.yaml

@@ -0,0 +1,22 @@
+# Learn more about charmcraft.yaml configuration at:
+# https://juju.is/docs/sdk/charmcraft-config
+type: "charm"
+bases:
+  - build-on:
+    - name: "ubuntu"
+      channel: "20.04"
+    run-on:
+    - name: "ubuntu"
+      channel: "20.04"
+  - build-on:
+    - name: "ubuntu"
+      channel: "18.04"
+    run-on:
+    - name: "ubuntu"
+      channel: "18.04"
+  - build-on:
+    - name: "ubuntu"
+      channel: "16.04"
+    run-on:
+    - name: "ubuntu"
+      channel: "16.04"

test/charms/test_smoke/config.yaml

@@ -0,0 +1,10 @@
+# Copyright 2022 Penelope Valentine Gale
+# See LICENSE file for licensing details.
+#
+# TEMPLATE-TODO: change this example to suit your needs.
+# If you don't need a config, you can remove the file entirely.
+# It ties in to the example _on_config_changed handler in src/charm.py
+#
+# Learn more about config at: https://juju.is/docs/sdk/config
+
+options: {}

test/charms/test_smoke/metadata.yaml

@@ -0,0 +1,12 @@
+# Copyright 2022 Penelope Valentine Gale
+# See LICENSE file for licensing details.
+
+# For a complete list of supported options, see:
+# https://juju.is/docs/sdk/metadata-reference
+name: smoke
+display-name: |
+  smoke
+description: |
+  smoke test charm
+summary: |
+  basic minimal charm for running smoke tests

test/charms/test_smoke/src/charm.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Charm the service.
+
+Refer to the following post for a quick-start guide that will help you
+develop a new k8s charm using the Operator Framework:
+
+    https://discourse.charmhub.io/t/4208
+"""
+
+import logging
+
+from ops.charm import CharmBase
+from ops.main import main
+from ops.model import ActiveStatus
+
+logger = logging.getLogger(__name__)
+
+
+class SmokeCharm(CharmBase):
+    """Charm the service."""
+
+    def __init__(self, *args):
+        super().__init__(*args)
+        self.framework.observe(self.on.install, self._on_install)
+
+    def _on_install(self, event):
+        self.unit.status = ActiveStatus()
+
+
+if __name__ == "__main__":
+    main(SmokeCharm)

test/smoke/test_smoke.py

@@ -0,0 +1,40 @@
+# Copyright 2022 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Learn more about testing at: https://juju.is/docs/sdk/testing
+
+import logging
+
+from pytest_operator.plugin import OpsTest
+
+logger = logging.getLogger(__name__)
+
+
+CURRENT_CHANNEL = '20.04'  # Focal
+
+
+async def test_smoke(ops_test: OpsTest):
+    # Verify that we can deploy charms from supported series.
+
+    # Build the charm. (We just build it for focal -- it *should* work to deploy it on
+    # older versions of Juju.)
+    charm = await ops_test.build_charm("./test/charms/test_smoke/")
+
+    for series in ['focal', 'bionic', 'xenial']:
+        app = await ops_test.model.deploy(
+            charm, series=series, application_name="{}-smoke".format(series))
+        await ops_test.model.wait_for_idle(timeout=600)
+
+        assert app.status == "active", "Series {} failed with '{}' status".format(
+            series, app.status)

tox.ini

@@ -63,7 +63,7 @@ commands =
 
 [testenv:unit]
 description = Run unit tests
-passenv = 
+passenv =
     RUN_REAL_PEBBLE_TESTS
     PEBBLE
 deps =
@@ -74,7 +74,8 @@ deps =
     coverage[toml]
     -r{toxinidir}/requirements.txt
 commands =
-    coverage run --source={[vars]src_path} -m pytest -v --tb native {posargs} 
+    coverage run --source={[vars]src_path} \
+             -m pytest --ignore={[vars]tst_path}smoke -v --tb native {posargs} 
     coverage report
 
 [testenv:pebble]
@@ -91,3 +92,21 @@ deps =
     -r{toxinidir}/requirements.txt
 commands =
     bash -c "umask 0; (pebble run --http=':4000' --create-dirs &>/dev/null & ) ; sleep 1; pytest -v --tb native -k RealPebble {posargs} ; killall -y 3m pebble"
+
+[testenv:smoke]
+description = Run a smoke test against a Juju controller.
+whitelist_externals = juju
+                      charmcraft
+                      bash
+deps =
+    pytest
+    pytest-operator
+commands =
+    # Build a source tarball for ops, and drop it into the root directory of the smoke test charm.
+    bash -c 'rm -vf ./test/charms/test_smoke/*.tar.gz  # Cleanup old builds'
+    python {toxinidir}/setup.py sdist --dist-dir={toxinidir}/test/charms/test_smoke/
+    # Inject the tarball into the smoke test charm's requirements.
+    bash -c 'echo "./$(ls -1 ./test/charms/test_smoke/ | grep tar.gz)" > ./test/charms/test_smoke/requirements.txt'
+
+    # Run our smoke tests (this will build the charm, then run the tests).
+    pytest -v --tb native --log-cli-level=INFO -s {posargs} {toxinidir}/test/smoke/