Initial code for test about upgrade from stable

.github/workflows/ci.yaml

@@ -82,6 +82,7 @@ jobs:
           - password-rotation-integration
           - plugins-integration
           - tls-integration
+          - upgrade-from-stable-integration
         agent-versions:
           - "2.9.44"  # renovate: latest juju 2
           - "3.1.5"  # renovate: latest juju 3

src/dependency.json

@@ -9,6 +9,6 @@
     "dependencies": {},
     "name": "charmed-postgresql",
     "upgrade_supported": "^14",
-    "version": "14.8"
+    "version": "14.9"
   }
 }

tests/integration/ha_tests/test_upgrade_from_stable.py

@@ -0,0 +1,115 @@
+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+import logging
+
+import pytest
+from pytest_operator.plugin import OpsTest
+
+from tests.integration.ha_tests.helpers import (
+    APPLICATION_NAME,
+    are_writes_increasing,
+    check_writes,
+    start_continuous_writes,
+)
+from tests.integration.helpers import (
+    DATABASE_APP_NAME,
+    count_switchovers,
+    get_leader_unit,
+    get_primary,
+)
+
+logger = logging.getLogger(__name__)
+
+TIMEOUT = 5 * 60
+
+
+@pytest.mark.abort_on_fail
+async def test_deploy_stable(ops_test: OpsTest) -> None:
+    """Simple test to ensure that the PostgreSQL and application charms get deployed."""
+    await ops_test.model.deploy(
+        DATABASE_APP_NAME,
+        num_units=2,
+        channel="14/edge",
+        trust=True,
+    ),
+    await ops_test.model.deploy(
+        APPLICATION_NAME,
+        num_units=1,
+        channel="latest/edge",
+    )
+    logger.info("Wait for applications to become active")
+    async with ops_test.fast_forward():
+        await ops_test.model.wait_for_idle(
+            apps=[DATABASE_APP_NAME, APPLICATION_NAME], status="active", timeout=(20 * 60)
+        )
+    # assert len(ops_test.model.applications[DATABASE_APP_NAME].units) == 3
+
+
+@pytest.mark.abort_on_fail
+async def test_pre_upgrade_check(ops_test: OpsTest) -> None:
+    """Test that the pre-upgrade-check action runs successfully."""
+    application = ops_test.model.applications[DATABASE_APP_NAME]
+    if "pre-upgrade-check" not in await application.get_actions():
+        logger.info("skipping the test because the charm from 14/stable doesn't support upgrade")
+        return
+
+    logger.info("Get leader unit")
+    leader_unit = await get_leader_unit(ops_test, DATABASE_APP_NAME)
+    assert leader_unit is not None, "No leader unit found"
+
+    logger.info("Run pre-upgrade-check action")
+    action = await leader_unit.run_action("pre-upgrade-check")
+    await action.wait()
+
+
+@pytest.mark.abort_on_fail
+async def test_upgrade_from_stable(ops_test: OpsTest):
+    """Test updating from stable channel."""
+    # Start an application that continuously writes data to the database.
+    logger.info("starting continuous writes to the database")
+    await start_continuous_writes(ops_test, DATABASE_APP_NAME)
+
+    # Check whether writes are increasing.
+    logger.info("checking whether writes are increasing")
+    await are_writes_increasing(ops_test)
+
+    primary_name = await get_primary(ops_test, f"{DATABASE_APP_NAME}/0")
+    initial_number_of_switchovers = count_switchovers(ops_test, primary_name)
+
+    application = ops_test.model.applications[DATABASE_APP_NAME]
+    actions = await application.get_actions()
+
+    logger.info("Build charm locally")
+    charm = await ops_test.build_charm(".")
+
+    logger.info("Refresh the charm")
+    await application.refresh(path=charm)
+
+    logger.info("Wait for upgrade to complete")
+    async with ops_test.fast_forward("60s"):
+        await ops_test.model.block_until(
+            lambda: ops_test.model.applications[DATABASE_APP_NAME].units[0].workload_status_message
+            == "upgrade completed",
+            timeout=TIMEOUT,
+        )
+        await ops_test.model.wait_for_idle(
+            apps=[DATABASE_APP_NAME], status="active", idle_period=30, timeout=TIMEOUT
+        )
+
+    # Check whether writes are increasing.
+    logger.info("checking whether writes are increasing")
+    await are_writes_increasing(ops_test)
+
+    # Verify that no writes to the database were missed after stopping the writes
+    # (check that all the units have all the writes).
+    logger.info("checking whether no writes were lost")
+    await check_writes(ops_test)
+
+    # Check the number of switchovers.
+    if "pre-upgrade-check" in actions:
+        logger.info("checking the number of switchovers")
+        final_number_of_switchovers = count_switchovers(ops_test, primary_name)
+        assert (
+            final_number_of_switchovers - initial_number_of_switchovers
+        ) <= 2, "Number of switchovers is greater than 2"

tests/integration/helpers.py

@@ -241,6 +241,13 @@ def convert_records_to_dict(records: List[tuple]) -> dict:
     return records_dict
 
 
+def count_switchovers(ops_test: OpsTest, unit_name: str) -> int:
+    """Return the number of performed switchovers."""
+    unit_address = get_unit_address(ops_test, unit_name)
+    switchover_history_info = requests.get(f"http://{unit_address}:8008/history")
+    return len(switchover_history_info.json())
+
+
 def db_connect(host: str, password: str) -> psycopg2.extensions.connection:
     """Returns psycopg2 connection object linked to postgres db in the given host.
 
@@ -559,6 +566,16 @@ async def get_landscape_api_credentials(ops_test: OpsTest) -> List[str]:
     return output
 
 
+async def get_leader_unit(ops_test: OpsTest, app: str) -> Optional[Unit]:
+    leader_unit = None
+    for unit in ops_test.model.applications[app].units:
+        if await unit.is_leader_from_status():
+            leader_unit = unit
+            break
+
+    return leader_unit
+
+
 async def get_machine_from_unit(ops_test: OpsTest, unit_name: str) -> str:
     """Get the name of the machine from a specific unit.
 

tox.ini

@@ -182,6 +182,17 @@ commands =
     pip install juju=={env:LIBJUJU}
     poetry run pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/test_tls.py
 
+[testenv:upgrade-from-stable-integration-{juju2, juju3}]
+description = Run upgrade from stable integration tests
+pass_env =
+    {[testenv]pass_env}
+    CI
+    CI_PACKED_CHARMS
+commands =
+    poetry install --with integration
+    pip install juju=={env:LIBJUJU}
+    poetry run pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/ha_tests/test_upgrade_from_stable.py
+
 [testenv:integration-{juju2, juju3}]
 description = Run all integration tests
 pass_env =