fix unit tests

[Abuelodelanada]

Bug Description

The unit test are broken:

https://github.com/canonical/cos-proxy-operator/actions/runs/24735374187/job/72360682142?pr=230

To Reproduce

1. tox -e unit

Environment

main branc

Relevant log output

=================================== FAILURES ===================================
_ COSProxyCharmTest.test_alert_rules_are_forwarded_on_adding_prometheus_then_targets _
Traceback (most recent call last):
  File "/usr/lib/python3.12/unittest/case.py", line 58, in testPartExecutor
    yield
  File "/usr/lib/python3.12/unittest/case.py", line 634, in run
    self._callTestMethod(testMethod)
  File "/usr/lib/python3.12/unittest/case.py", line 589, in _callTestMethod
    if method() is not None:
       ^^^^^^^^
  File "/usr/lib/python3.12/unittest/mock.py", line 1390, in patched
    return func(*newargs, **newkeywargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_charm.py", line 434, in test_alert_rules_are_forwarded_on_adding_prometheus_then_targets
    self.assertCountEqual(groups, GENERIC_RULES + BUNDLED_RULES + expected_groups)
  File "/usr/lib/python3.12/unittest/case.py", line 1216, in assertCountEqual
    self.fail(msg)
  File "/usr/lib/python3.12/unittest/case.py", line 715, in fail
    raise self.failureException(msg)
AssertionError: Element counts were not equal:

Diff is 3712 characters long. Set self.maxDiff to None to see it.
------------------------------ Captured log call -------------------------------
DEBUG    root:storage.py:68 Initializing SQLite local storage: :memory:.
DEBUG    cosl.cos_tool:cos_tool.py:191 Could not locate cos-tool at: "cos-tool-amd64"
DEBUG    cosl.cos_tool:cos_tool.py:62 Skipping injection of juju topology as label matchers
DEBUG    cosl.cos_tool:cos_tool.py:155 `cos-tool` unavailable. Leaving expression unchanged: vector_uptime_seconds < (vector_uptime_seconds offset 5m)
DEBUG    cosl.rules:rules.py:350 Reading rule from src/prometheus_alert_rules/vector_restarted.rule
DEBUG    cosl.cos_tool:cos_tool.py:155 `cos-tool` unavailable. Leaving expression unchanged: up < 1
DEBUG    cosl.cos_tool:cos_tool.py:155 `cos-tool` unavailable. Leaving expression unchanged: absent(up)
_ COSProxyCharmTest.test_alert_rules_are_forwarded_on_adding_targets_then_prometheus _
Traceback (most recent call last):
  File "/usr/lib/python3.12/unittest/case.py", line 58, in testPartExecutor
    yield
  File "/usr/lib/python3.12/unittest/case.py", line 634, in run
    self._callTestMethod(testMethod)
  File "/usr/lib/python3.12/unittest/case.py", line 589, in _callTestMethod
    if method() is not None:
       ^^^^^^^^
  File "/usr/lib/python3.12/unittest/mock.py", line 1390, in patched
    return func(*newargs, **newkeywargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_charm.py", line 485, in test_alert_rules_are_forwarded_on_adding_targets_then_prometheus
    self.assertCountEqual(groups, GENERIC_RULES + BUNDLED_RULES + expected_groups)
  File "/usr/lib/python3.12/unittest/case.py", line 1216, in assertCountEqual
    self.fail(msg)
  File "/usr/lib/python3.12/unittest/case.py", line 715, in fail
    raise self.failureException(msg)
AssertionError: Element counts were not equal:

Diff is 3712 characters long. Set self.maxDiff to None to see it.
------------------------------ Captured log call -------------------------------
DEBUG    root:storage.py:68 Initializing SQLite local storage: :memory:.
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/src/vector.py:44: SyntaxWarning: invalid escape sequence '\d'
    DEFAULT_VECTOR_CONFIG = """

tests/unit/test_charm.py: 17 warnings
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_charm.py:235: PendingDeprecationWarning: Harness is deprecated. For the recommended approach, see: https://documentation.ubuntu.com/ops/latest/howto/write-unit-tests-for-a-charm/
    self.harness = Harness(COSProxyCharm)

tests/unit/test_charm.py: 1 warning
tests/unit/test_outgoing_relation_data.py: 14 warnings
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/lib/charms/grafana_agent/v0/cos_agent.py:690: PydanticDeprecatedSince20: The `json` method is deprecated; use `model_dump_json` instead. Deprecated in Pydantic V2.0 to be removed in V3.0. See Pydantic V2 Migration Guide at https://errors.pydantic.dev/2.13/migration/
    relation.data[self._charm.unit][data.KEY] = data.json()

tests/unit/test_endpoint_aggregator.py: 12 warnings
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_endpoint_aggregator.py:135: PendingDeprecationWarning: Harness is deprecated. For the recommended approach, see: https://documentation.ubuntu.com/ops/latest/howto/write-unit-tests-for-a-charm/
    self.harness = Harness(EndpointAggregatorCharm, meta=AGGREGATOR_META)

tests/unit/test_endpoint_aggregator.py::TestEndpointAggregatorWithRelabeling::test_adding_prometheus_then_target_with_bad_dns_keeps_input
tests/unit/test_endpoint_aggregator.py::TestEndpointAggregatorWithRelabeling::test_adding_prometheus_then_target_with_good_dns_adds_label
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_endpoint_aggregator.py:634: PendingDeprecationWarning: Harness is deprecated. For the recommended approach, see: https://documentation.ubuntu.com/ops/latest/howto/write-unit-tests-for-a-charm/
    self.harness = Harness(EndpointResolvingAggregatorCharm, meta=AGGREGATOR_META)

tests/unit/test_outgoing_relation_data.py::TestRelationMonitors::test_cos_agent_with_downstream_prometheus
tests/unit/test_outgoing_relation_data.py::TestRelationMonitors::test_only_cos_agent
tests/unit/test_outgoing_relation_data.py::TestRelationMonitors::test_only_prometheus
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_outgoing_relation_data.py:82: PendingDeprecationWarning: Harness is deprecated. For the recommended approach, see: https://documentation.ubuntu.com/ops/latest/howto/write-unit-tests-for-a-charm/
    self.harness = Harness(COSProxyCharm)

tests/unit/test_relation_monitors.py::TestRelationMonitors::test_monitors_changed
tests/unit/test_relation_monitors.py::TestRelationMonitors::test_prometheus
  /home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit/test_relation_monitors.py:54: PendingDeprecationWarning: Harness is deprecated. For the recommended approach, see: https://documentation.ubuntu.com/ops/latest/howto/write-unit-tests-for-a-charm/
    self.harness = Harness(COSProxyCharm)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
=========================== short test summary info ============================
FAILED tests/unit/test_charm.py::COSProxyCharmTest::test_alert_rules_are_forwarded_on_adding_prometheus_then_targets - AssertionError: Element counts were not equal:
FAILED tests/unit/test_charm.py::COSProxyCharmTest::test_alert_rules_are_forwarded_on_adding_targets_then_prometheus - AssertionError: Element counts were not equal:
FAILED tests/unit/test_charm.py::COSProxyCharmTest::test_alert_rules_removal_differentiates_between_applications - AssertionError: Element counts were not equal:
FAILED tests/unit/test_charm.py::COSProxyCharmTest::test_multiple_alert_rules_are_forwarded - AssertionError: Element counts were not equal:
FAILED tests/unit/test_charm.py::COSProxyCharmTest::test_removing_alert_rules_differentiates_between_units - AssertionError: Element counts were not equal:
================== 5 failed, 40 passed, 53 warnings in 2.35s ===================
unit: exit 1 (6.31 seconds) /home/runner/work/cos-proxy-operator/cos-proxy-operator> uv run --frozen --isolated --extra=dev coverage run --source=/home/runner/work/cos-proxy-operator/cos-proxy-operator/src -m pytest /home/runner/work/cos-proxy-operator/cos-proxy-operator/tests/unit pid=3058
  unit: FAIL code 1 (7.50=setup[0.88]+cmd[0.30,6.31] seconds)
  evaluation failed :( (7.53 seconds)
Error: Process completed with exit code 1.

Additional context

No response