From 7219d1ed1a118abbfca23aeacf3b7bf67e81a937 Mon Sep 17 00:00:00 2001
From: Dragomir Penev <6687393+dragomirp@users.noreply.github.com>
Date: Mon, 23 Sep 2024 19:12:27 +0300
Subject: [PATCH] [MISC] Bump libs and remove TestCase (#622)

* Bump libs

* Remove test case asserts

* Excessive assert
---
 lib/charms/tempo_k8s/v2/tracing.py |  19 +-
 tests/unit/test_backups.py         | 587 ++++++++++++-----------------
 tests/unit/test_charm.py           |  16 +-
 tests/unit/test_cluster.py         |  51 +--
 4 files changed, 289 insertions(+), 384 deletions(-)

diff --git a/lib/charms/tempo_k8s/v2/tracing.py b/lib/charms/tempo_k8s/v2/tracing.py
index dfb23365fb..81bf1f1f5f 100644
--- a/lib/charms/tempo_k8s/v2/tracing.py
+++ b/lib/charms/tempo_k8s/v2/tracing.py
@@ -97,7 +97,7 @@ def __init__(self, *args):
 )
 from ops.framework import EventSource, Object
 from ops.model import ModelError, Relation
-from pydantic import BaseModel, ConfigDict, Field
+from pydantic import BaseModel, Field
 
 # The unique Charmhub library identifier, never change it
 LIBID = "12977e9aa0b34367903d8afeb8c3d85d"
@@ -107,7 +107,7 @@ def __init__(self, *args):
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 8
+LIBPATCH = 10
 
 PYDEPS = ["pydantic"]
 
@@ -338,7 +338,7 @@ class Config:
     class ProtocolType(BaseModel):
         """Protocol Type."""
 
-        model_config = ConfigDict(
+        model_config = ConfigDict(  # type: ignore
             # Allow serializing enum values.
             use_enum_values=True
         )
@@ -902,7 +902,16 @@ def _get_endpoint(
     def get_endpoint(
         self, protocol: ReceiverProtocol, relation: Optional[Relation] = None
     ) -> Optional[str]:
-        """Receiver endpoint for the given protocol."""
+        """Receiver endpoint for the given protocol.
+
+        It could happen that this function gets called before the provider publishes the endpoints.
+        In such a scenario, if a non-leader unit calls this function, a permission denied exception will be raised due to
+        restricted access. To prevent this, this function needs to be guarded by the `is_ready` check.
+
+        Raises:
+        ProtocolNotRequestedError:
+            If the charm unit is the leader unit and attempts to obtain an endpoint for a protocol it did not request.
+        """
         endpoint = self._get_endpoint(relation or self._relation, protocol=protocol)
         if not endpoint:
             requested_protocols = set()
@@ -925,7 +934,7 @@ def get_endpoint(
 def charm_tracing_config(
     endpoint_requirer: TracingEndpointRequirer, cert_path: Optional[Union[Path, str]]
 ) -> Tuple[Optional[str], Optional[str]]:
-    """Utility function to determine the charm_tracing config you will likely want.
+    """Return the charm_tracing config you likely want.
 
     If no endpoint is provided:
      disable charm tracing.
diff --git a/tests/unit/test_backups.py b/tests/unit/test_backups.py
index c46a4e272d..4769e9251f 100644
--- a/tests/unit/test_backups.py
+++ b/tests/unit/test_backups.py
@@ -3,7 +3,6 @@
 from pathlib import PosixPath
 from subprocess import PIPE, CompletedProcess, TimeoutExpired
 from typing import OrderedDict
-from unittest import TestCase
 from unittest.mock import ANY, MagicMock, PropertyMock, call, mock_open, patch
 
 import botocore as botocore
@@ -26,9 +25,6 @@
 FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE = "failed to initialize stanza, check your S3 settings"
 S3_PARAMETERS_RELATION = "s3-parameters"
 
-# used for assert functions
-tc = TestCase()
-
 
 @pytest.fixture(autouse=True)
 def harness():
@@ -43,18 +39,15 @@ def harness():
 
 
 def test_stanza_name(harness):
-    tc.assertEqual(
-        harness.charm.backup.stanza_name,
-        f"{harness.charm.model.name}.{harness.charm.cluster_name}",
+    assert (
+        harness.charm.backup.stanza_name
+        == f"{harness.charm.model.name}.{harness.charm.cluster_name}"
     )
 
 
 def test_tls_ca_chain_filename(harness):
     # Test when the TLS CA chain is not available.
-    tc.assertEqual(
-        harness.charm.backup._tls_ca_chain_filename,
-        "",
-    )
+    assert harness.charm.backup._tls_ca_chain_filename == ""
 
     # Test when the TLS CA chain is available.
     with harness.hooks_disabled():
@@ -70,33 +63,30 @@ def test_tls_ca_chain_filename(harness):
                 "tls-ca-chain": '["fake-tls-ca-chain"]',
             },
         )
-    tc.assertEqual(
-        harness.charm.backup._tls_ca_chain_filename,
-        "/var/snap/charmed-postgresql/common/pgbackrest-tls-ca-chain.crt",
+    assert (
+        harness.charm.backup._tls_ca_chain_filename
+        == "/var/snap/charmed-postgresql/common/pgbackrest-tls-ca-chain.crt"
     )
 
 
 def test_are_backup_settings_ok(harness):
     # Test without S3 relation.
-    tc.assertEqual(
-        harness.charm.backup._are_backup_settings_ok(),
-        (False, "Relation with s3-integrator charm missing, cannot create/restore backup."),
+    assert harness.charm.backup._are_backup_settings_ok() == (
+        False,
+        "Relation with s3-integrator charm missing, cannot create/restore backup.",
     )
 
     # Test when there are missing S3 parameters.
     harness.add_relation(S3_PARAMETERS_RELATION, "s3-integrator")
-    tc.assertEqual(
-        harness.charm.backup._are_backup_settings_ok(),
-        (False, "Missing S3 parameters: ['bucket', 'access-key', 'secret-key']"),
+    assert harness.charm.backup._are_backup_settings_ok() == (
+        False,
+        "Missing S3 parameters: ['bucket', 'access-key', 'secret-key']",
     )
 
     # Test when all required parameters are provided.
     with patch("charm.PostgreSQLBackups._retrieve_s3_parameters") as _retrieve_s3_parameters:
         _retrieve_s3_parameters.return_value = ["bucket", "access-key", "secret-key"], []
-        tc.assertEqual(
-            harness.charm.backup._are_backup_settings_ok(),
-            (True, None),
-        )
+        assert harness.charm.backup._are_backup_settings_ok() == (True, None)
 
 
 def test_can_initialise_stanza(harness):
@@ -104,10 +94,7 @@ def test_can_initialise_stanza(harness):
         # Test when Patroni or PostgreSQL hasn't started yet
         # and the unit hasn't joined the peer relation yet.
         _member_started.return_value = False
-        tc.assertEqual(
-            harness.charm.backup._can_initialise_stanza,
-            False,
-        )
+        assert not harness.charm.backup._can_initialise_stanza
 
         # Test when the unit hasn't configured TLS yet while other unit already has TLS enabled.
         harness.add_relation_unit(
@@ -119,17 +106,11 @@ def test_can_initialise_stanza(harness):
                 f"{harness.charm.app.name}/1",
                 {"tls": "enabled"},
             )
-        tc.assertEqual(
-            harness.charm.backup._can_initialise_stanza,
-            False,
-        )
+        assert not harness.charm.backup._can_initialise_stanza
 
         # Test when everything is ok to initialise the stanza.
         _member_started.return_value = True
-        tc.assertEqual(
-            harness.charm.backup._can_initialise_stanza,
-            True,
-        )
+        assert harness.charm.backup._can_initialise_stanza
 
 
 def test_can_unit_perform_backup(harness):
@@ -144,18 +125,18 @@ def test_can_unit_perform_backup(harness):
         peer_rel_id = harness.model.get_relation(PEER).id
         # Test when the charm fails to retrieve the primary.
         _is_primary.side_effect = RetryError(last_attempt=1)
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "Unit cannot perform backups as the database seems to be offline"),
+        assert harness.charm.backup._can_unit_perform_backup() == (
+            False,
+            "Unit cannot perform backups as the database seems to be offline",
         )
 
         # Test when the unit is in a blocked state.
         _is_primary.side_effect = None
         _is_primary.return_value = True
         harness.charm.unit.status = BlockedStatus("fake blocked state")
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "Unit is in a blocking state"),
+        assert harness.charm.backup._can_unit_perform_backup() == (
+            False,
+            "Unit is in a blocking state",
         )
 
         # Test when running the check in the primary, there are replicas and TLS is enabled.
@@ -167,9 +148,9 @@ def test_can_unit_perform_backup(harness):
                 harness.charm.unit.name,
                 {"tls": "True"},
             )
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "Unit cannot perform backups as it is the cluster primary"),
+        assert harness.charm.backup._can_unit_perform_backup() == (
+            False,
+            "Unit cannot perform backups as it is the cluster primary",
         )
 
         # Test when running the check in a replica and TLS is disabled.
@@ -180,24 +161,24 @@ def test_can_unit_perform_backup(harness):
                 harness.charm.unit.name,
                 {"tls": ""},
             )
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "Unit cannot perform backups as TLS is not enabled"),
+        assert harness.charm.backup._can_unit_perform_backup() == (
+            False,
+            "Unit cannot perform backups as TLS is not enabled",
         )
 
         # Test when Patroni or PostgreSQL hasn't started yet.
         _is_primary.return_value = True
         _member_started.return_value = False
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "Unit cannot perform backups as it's not in running state"),
+        assert harness.charm.backup._can_unit_perform_backup() == (
+            False,
+            "Unit cannot perform backups as it's not in running state",
         )
 
         # Test when the stanza was not initialised yet.
         _member_started.return_value = True
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "Stanza was not initialised"),
+        assert harness.charm.backup._can_unit_perform_backup() == (
+            False,
+            "Stanza was not initialised",
         )
 
         # Test when S3 parameters are not ok.
@@ -208,17 +189,11 @@ def test_can_unit_perform_backup(harness):
                 {"stanza": harness.charm.backup.stanza_name},
             )
         _are_backup_settings_ok.return_value = (False, "fake error message")
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (False, "fake error message"),
-        )
+        assert harness.charm.backup._can_unit_perform_backup() == (False, "fake error message")
 
         # Test when everything is ok to run a backup.
         _are_backup_settings_ok.return_value = (True, None)
-        tc.assertEqual(
-            harness.charm.backup._can_unit_perform_backup(),
-            (True, None),
-        )
+        assert harness.charm.backup._can_unit_perform_backup() == (True, None)
 
 
 def test_can_use_s3_repository(harness):
@@ -246,14 +221,15 @@ def test_can_use_s3_repository(harness):
 
         # Test when nothing is returned from the pgBackRest info command.
         _execute_command.side_effect = TimeoutExpired(cmd="fake command", timeout=30)
-        with tc.assertRaises(TimeoutError):
+        with pytest.raises(TimeoutError):
             harness.charm.backup.can_use_s3_repository()
+            assert False
 
         _execute_command.side_effect = None
         _execute_command.return_value = (1, "", "")
-        tc.assertEqual(
-            harness.charm.backup.can_use_s3_repository(),
-            (False, FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE),
+        assert harness.charm.backup.can_use_s3_repository() == (
+            False,
+            FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE,
         )
 
         # Test when the unit is a replica.
@@ -263,16 +239,12 @@ def test_can_use_s3_repository(harness):
             "",
         )
         _execute_command.return_value = pgbackrest_info_same_cluster_backup_output
-        tc.assertEqual(
-            harness.charm.backup.can_use_s3_repository(),
-            (True, None),
-        )
+        assert harness.charm.backup.can_use_s3_repository() == (True, None)
 
         # Assert that the stanza name is still in the unit relation data.
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
-            {"stanza": harness.charm.backup.stanza_name},
-        )
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "stanza": harness.charm.backup.stanza_name
+        }
 
         # Test when the unit is the leader and the workload is running,
         # but an exception happens when retrieving the cluster system id.
@@ -283,11 +255,9 @@ def test_can_use_s3_repository(harness):
         ]
         with harness.hooks_disabled():
             harness.set_leader()
-        with tc.assertRaises(Exception):
-            tc.assertEqual(
-                harness.charm.backup.can_use_s3_repository(),
-                (False, ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE),
-            )
+        with pytest.raises(Exception, match="fake error"):
+            harness.charm.backup.can_use_s3_repository()
+            assert False
         _update_config.assert_not_called()
         _member_started.assert_not_called()
         _reload_patroni_configuration.assert_not_called()
@@ -313,16 +283,16 @@ def test_can_use_s3_repository(harness):
                 harness.charm.app.name,
                 {"stanza": harness.charm.backup.stanza_name},
             )
-        tc.assertEqual(
-            harness.charm.backup.can_use_s3_repository(),
-            (False, ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE),
+        assert harness.charm.backup.can_use_s3_repository() == (
+            False,
+            ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE,
         )
         _update_config.assert_called_once()
         _member_started.assert_called_once()
         _reload_patroni_configuration.assert_called_once()
 
         # Assert that the stanza name is not present in the unit relation data anymore.
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
 
         # Test when the cluster system id can be retrieved, but it's different from the stanza system id.
         _update_config.reset_mock()
@@ -348,16 +318,16 @@ def test_can_use_s3_repository(harness):
                 harness.charm.app.name,
                 {"stanza": harness.charm.backup.stanza_name},
             )
-        tc.assertEqual(
-            harness.charm.backup.can_use_s3_repository(),
-            (False, ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE),
+        assert harness.charm.backup.can_use_s3_repository() == (
+            False,
+            ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE,
         )
         _update_config.assert_called_once()
         _member_started.assert_called_once()
         _reload_patroni_configuration.assert_called_once()
 
         # Assert that the stanza name is not present in the unit relation data anymore.
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
 
         # Test when the workload is not running.
         _update_config.reset_mock()
@@ -374,16 +344,16 @@ def test_can_use_s3_repository(harness):
             pgbackrest_info_same_cluster_backup_output,
             other_instance_system_identifier_output,
         ]
-        tc.assertEqual(
-            harness.charm.backup.can_use_s3_repository(),
-            (False, ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE),
+        assert harness.charm.backup.can_use_s3_repository() == (
+            False,
+            ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE,
         )
         _update_config.assert_called_once()
         _member_started.assert_called_once()
         _reload_patroni_configuration.assert_not_called()
 
         # Assert that the stanza name is not present in the unit relation data anymore.
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
 
         # Test when there is no backup from another cluster in the S3 repository.
         with harness.hooks_disabled():
@@ -396,36 +366,30 @@ def test_can_use_s3_repository(harness):
             pgbackrest_info_same_cluster_backup_output,
             same_instance_system_identifier_output,
         ]
-        tc.assertEqual(
-            harness.charm.backup.can_use_s3_repository(),
-            (True, None),
-        )
+        assert harness.charm.backup.can_use_s3_repository() == (True, None)
 
         # Assert that the stanza name is still in the unit relation data.
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
-            {"stanza": harness.charm.backup.stanza_name},
-        )
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "stanza": harness.charm.backup.stanza_name
+        }
 
 
 def test_construct_endpoint(harness):
     # Test with an AWS endpoint without region.
     s3_parameters = {"endpoint": "https://s3.amazonaws.com", "region": ""}
-    tc.assertEqual(
-        harness.charm.backup._construct_endpoint(s3_parameters), "https://s3.amazonaws.com"
-    )
+    assert harness.charm.backup._construct_endpoint(s3_parameters) == "https://s3.amazonaws.com"
 
     # Test with an AWS endpoint with region.
     s3_parameters["region"] = "us-east-1"
-    tc.assertEqual(
-        harness.charm.backup._construct_endpoint(s3_parameters),
-        "https://s3.us-east-1.amazonaws.com",
+    assert (
+        harness.charm.backup._construct_endpoint(s3_parameters)
+        == "https://s3.us-east-1.amazonaws.com"
     )
 
     # Test with another cloud endpoint.
     s3_parameters["endpoint"] = "https://storage.googleapis.com"
-    tc.assertEqual(
-        harness.charm.backup._construct_endpoint(s3_parameters), "https://storage.googleapis.com"
+    assert (
+        harness.charm.backup._construct_endpoint(s3_parameters) == "https://storage.googleapis.com"
     )
 
 
@@ -459,8 +423,9 @@ def test_create_bucket_if_not_exists(harness, tls_ca_chain_filename):
             [],
         )
         _resource.side_effect = ValueError
-        with tc.assertRaises(ValueError):
+        with pytest.raises(ValueError):
             harness.charm.backup._create_bucket_if_not_exists()
+            assert False
 
         # Test when the bucket already exists.
         _resource.reset_mock()
@@ -495,8 +460,9 @@ def test_create_bucket_if_not_exists(harness, tls_ca_chain_filename):
             error_response={"Error": {"Code": 1, "message": "fake error"}},
             operation_name="fake operation name",
         )
-        with tc.assertRaises(ClientError):
+        with pytest.raises(ClientError):
             harness.charm.backup._create_bucket_if_not_exists()
+            assert False
         head_bucket.assert_called_once()
         create.assert_called_once()
         wait_until_exists.assert_not_called()
@@ -507,8 +473,9 @@ def test_create_bucket_if_not_exists(harness, tls_ca_chain_filename):
         head_bucket.side_effect = botocore.exceptions.ConnectTimeoutError(
             endpoint_url="fake endpoint URL"
         )
-        with tc.assertRaises(botocore.exceptions.ConnectTimeoutError):
+        with pytest.raises(botocore.exceptions.ConnectTimeoutError):
             harness.charm.backup._create_bucket_if_not_exists()
+            assert False
         head_bucket.assert_called_once()
         create.assert_not_called()
         wait_until_exists.assert_not_called()
@@ -522,7 +489,7 @@ def test_empty_data_files(harness):
     ):
         # Test when the data directory doesn't exist.
         _exists.return_value = False
-        tc.assertTrue(harness.charm.backup._empty_data_files())
+        assert harness.charm.backup._empty_data_files()
         _rmtree.assert_not_called()
 
         # Test when the removal of the data files fails.
@@ -530,13 +497,13 @@ def test_empty_data_files(harness):
         _exists.return_value = True
         _is_dir.return_value = True
         _rmtree.side_effect = OSError
-        tc.assertFalse(harness.charm.backup._empty_data_files())
+        assert not harness.charm.backup._empty_data_files()
         _rmtree.assert_called_once_with(path)
 
         # Test when data files are successfully removed.
         _rmtree.reset_mock()
         _rmtree.side_effect = None
-        tc.assertTrue(harness.charm.backup._empty_data_files())
+        assert harness.charm.backup._empty_data_files()
         _rmtree.assert_called_once_with(path)
 
 
@@ -553,19 +520,15 @@ def test_change_connectivity_to_database(harness):
 
         # Test when connectivity should be turned on.
         harness.charm.backup._change_connectivity_to_database(True)
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.unit),
-            {"connectivity": "on"},
-        )
+        assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {"connectivity": "on"}
         _update_config.assert_called_once()
 
         # Test when connectivity should be turned off.
         _update_config.reset_mock()
         harness.charm.backup._change_connectivity_to_database(False)
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.unit),
-            {"connectivity": "off"},
-        )
+        assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {
+            "connectivity": "off"
+        }
         _update_config.assert_called_once()
 
 
@@ -577,7 +540,7 @@ def test_execute_command(harness):
         # Test when the command fails.
         command = "rm -r /var/lib/postgresql/data/pgdata".split()
         _run.return_value = CompletedProcess(command, 1, b"", b"fake stderr")
-        tc.assertEqual(harness.charm.backup._execute_command(command), (1, "", "fake stderr"))
+        assert harness.charm.backup._execute_command(command) == (1, "", "fake stderr")
         _run.assert_called_once_with(
             command, input=None, stdout=PIPE, stderr=PIPE, preexec_fn=ANY, timeout=None
         )
@@ -588,10 +551,9 @@ def test_execute_command(harness):
         _getpwnam.reset_mock()
         _run.side_effect = None
         _run.return_value = CompletedProcess(command, 0, b"fake stdout", b"")
-        tc.assertEqual(
-            harness.charm.backup._execute_command(command, command_input=b"fake input", timeout=5),
-            (0, "fake stdout", ""),
-        )
+        assert harness.charm.backup._execute_command(
+            command, command_input=b"fake input", timeout=5
+        ) == (0, "fake stdout", "")
         _run.assert_called_once_with(
             command, input=b"fake input", stdout=PIPE, stderr=PIPE, preexec_fn=ANY, timeout=5
         )
@@ -698,16 +660,13 @@ def test_list_backups(harness):
     with patch("charm.PostgreSQLBackups._execute_command") as _execute_command:
         # Test when the command that list the backups fails.
         _execute_command.return_value = (1, "", "fake stderr")
-        with tc.assertRaises(ListBackupsError):
-            tc.assertEqual(
-                harness.charm.backup._list_backups(show_failed=True), OrderedDict[str, str]()
-            )
+        with pytest.raises(ListBackupsError):
+            harness.charm.backup._list_backups(show_failed=True)
+            assert False
 
         # Test when no backups are available.
         _execute_command.return_value = (0, "[]", "")
-        tc.assertEqual(
-            harness.charm.backup._list_backups(show_failed=True), OrderedDict[str, str]()
-        )
+        assert harness.charm.backup._list_backups(show_failed=True) == OrderedDict[str, str]()
 
         # Test when some backups are available.
         _execute_command.return_value = (
@@ -715,19 +674,15 @@ def test_list_backups(harness):
             '[{"backup":[{"label":"20230101-090000F","error":"fake error"},{"label":"20230101-100000F","error":null}],"name":"test-stanza"}]',
             "",
         )
-        tc.assertEqual(
-            harness.charm.backup._list_backups(show_failed=True),
-            OrderedDict[str, str]([
-                ("2023-01-01T09:00:00Z", "test-stanza"),
-                ("2023-01-01T10:00:00Z", "test-stanza"),
-            ]),
-        )
+        assert harness.charm.backup._list_backups(show_failed=True) == OrderedDict[str, str]([
+            ("2023-01-01T09:00:00Z", "test-stanza"),
+            ("2023-01-01T10:00:00Z", "test-stanza"),
+        ])
 
         # Test when some backups are available, but it's not desired to list failed backups.
-        tc.assertEqual(
-            harness.charm.backup._list_backups(show_failed=False),
-            OrderedDict[str, str]([("2023-01-01T10:00:00Z", "test-stanza")]),
-        )
+        assert harness.charm.backup._list_backups(show_failed=False) == OrderedDict[str, str]([
+            ("2023-01-01T10:00:00Z", "test-stanza")
+        ])
 
 
 def test_initialise_stanza(harness):
@@ -771,19 +726,18 @@ def test_initialise_stanza(harness):
             harness.charm.unit.status = BlockedStatus(blocked_state)
             harness.charm.backup._initialise_stanza()
             _execute_command.assert_called_once_with(stanza_creation_command)
-            tc.assertIsInstance(harness.charm.unit.status, BlockedStatus)
-            tc.assertEqual(
-                harness.charm.unit.status.message, FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE
-            )
+            assert isinstance(harness.charm.unit.status, BlockedStatus)
+            assert harness.charm.unit.status.message == FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE
 
             # Assert there is no stanza name in the application relation databag.
-            tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
+            assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
 
         # Test when the failure in the stanza creation is due to a timeout.
         _execute_command.reset_mock()
         _execute_command.return_value = (49, "", "fake stderr")
-        with tc.assertRaises(TimeoutError):
+        with pytest.raises(TimeoutError):
             harness.charm.backup._initialise_stanza()
+            assert False
 
         # Test when the archiving is working correctly (pgBackRest check command succeeds)
         # and the unit is not the leader.
@@ -791,15 +745,12 @@ def test_initialise_stanza(harness):
         _execute_command.return_value = (0, "fake stdout", "")
         _member_started.return_value = True
         harness.charm.backup._initialise_stanza()
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.unit),
-            {
-                "stanza": f"{harness.charm.model.name}.postgresql",
-                "init-pgbackrest": "True",
-            },
-        )
-        tc.assertIsInstance(harness.charm.unit.status, MaintenanceStatus)
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+        assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {
+            "stanza": f"{harness.charm.model.name}.postgresql",
+            "init-pgbackrest": "True",
+        }
+        assert isinstance(harness.charm.unit.status, MaintenanceStatus)
 
         # Test when the unit is the leader.
         with harness.hooks_disabled():
@@ -809,13 +760,13 @@ def test_initialise_stanza(harness):
             )
         harness.charm.backup._initialise_stanza()
         _update_config.assert_not_called()
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
-            {"stanza": "None.postgresql", "init-pgbackrest": "True"},
-        )
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "stanza": "None.postgresql",
+            "init-pgbackrest": "True",
+        }
         _member_started.assert_not_called()
         _reload_patroni_configuration.assert_not_called()
-        tc.assertIsInstance(harness.charm.unit.status, MaintenanceStatus)
+        assert isinstance(harness.charm.unit.status, MaintenanceStatus)
 
 
 def test_check_stanza(harness):
@@ -855,16 +806,14 @@ def test_check_stanza(harness):
         _execute_command.return_value = (49, "", "fake stderr")
         _member_started.return_value = True
         harness.charm.backup.check_stanza()
-        tc.assertEqual(_update_config.call_count, 2)
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
-        tc.assertEqual(_member_started.call_count, 5)
-        tc.assertEqual(_reload_patroni_configuration.call_count, 5)
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-        tc.assertIsInstance(harness.charm.unit.status, BlockedStatus)
-        tc.assertEqual(
-            harness.charm.unit.status.message, FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE
-        )
+        assert _update_config.call_count == 2
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+        assert _member_started.call_count == 5
+        assert _reload_patroni_configuration.call_count == 5
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+        assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+        assert isinstance(harness.charm.unit.status, BlockedStatus)
+        assert harness.charm.unit.status.message == FAILED_TO_INITIALIZE_STANZA_ERROR_MESSAGE
 
         # Test when the archiving is working correctly (pgBackRest check command succeeds)
         # and the unit is not the leader.
@@ -889,15 +838,14 @@ def test_check_stanza(harness):
         _update_config.assert_called_once()
         _member_started.assert_called_once()
         _reload_patroni_configuration.assert_called_once()
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
-            {"stanza": "test-stanza", "init-pgbackrest": "True"},
-        )
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.unit),
-            {"stanza": "test-stanza"},
-        )
-        tc.assertIsInstance(harness.charm.unit.status, ActiveStatus)
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "stanza": "test-stanza",
+            "init-pgbackrest": "True",
+        }
+        assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {
+            "stanza": "test-stanza"
+        }
+        assert isinstance(harness.charm.unit.status, ActiveStatus)
 
         # Test when the unit is the leader.
         harness.charm.unit.status = BlockedStatus("fake blocked state")
@@ -920,15 +868,13 @@ def test_check_stanza(harness):
         _update_config.assert_called_once()
         _member_started.assert_called_once()
         _reload_patroni_configuration.assert_called_once()
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
-            {"stanza": "test-stanza"},
-        )
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.unit),
-            {"stanza": "test-stanza"},
-        )
-        tc.assertIsInstance(harness.charm.unit.status, ActiveStatus)
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "stanza": "test-stanza"
+        }
+        assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {
+            "stanza": "test-stanza"
+        }
+        assert isinstance(harness.charm.unit.status, ActiveStatus)
 
 
 def test_coordinate_stanza_fields(harness):
@@ -940,9 +886,9 @@ def test_coordinate_stanza_fields(harness):
 
     # Test when the stanza name is neither in the application relation databag nor in the unit relation databag.
     harness.charm.backup.coordinate_stanza_fields()
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, new_unit), {})
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+    assert harness.get_relation_data(peer_rel_id, new_unit) == {}
 
     # Test when the stanza name is in the unit relation databag but the unit is not the leader.
     stanza_name = f"{harness.charm.model.name}.{harness.charm.app.name}"
@@ -951,61 +897,52 @@ def test_coordinate_stanza_fields(harness):
             peer_rel_id, new_unit_name, {"stanza": stanza_name, "init-pgbackrest": "True"}
         )
     harness.charm.backup.coordinate_stanza_fields()
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, new_unit),
-        {"stanza": stanza_name, "init-pgbackrest": "True"},
-    )
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+    assert harness.get_relation_data(peer_rel_id, new_unit) == {
+        "stanza": stanza_name,
+        "init-pgbackrest": "True",
+    }
 
     # Test when the unit is the leader.
     with harness.hooks_disabled():
         harness.set_leader()
     harness.charm.backup.coordinate_stanza_fields()
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, harness.charm.app),
-        {"stanza": stanza_name, "init-pgbackrest": "True"},
-    )
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, new_unit),
-        {"stanza": stanza_name, "init-pgbackrest": "True"},
-    )
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+        "stanza": stanza_name,
+        "init-pgbackrest": "True",
+    }
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+    assert harness.get_relation_data(peer_rel_id, new_unit) == {
+        "stanza": stanza_name,
+        "init-pgbackrest": "True",
+    }
 
     # Test when the stanza was already checked in the primary non-leader unit.
     with harness.hooks_disabled():
         harness.update_relation_data(peer_rel_id, new_unit_name, {"init-pgbackrest": ""})
     harness.charm.backup.coordinate_stanza_fields()
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, harness.charm.app),
-        {"stanza": stanza_name},
-    )
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, new_unit), {"stanza": stanza_name})
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {"stanza": stanza_name}
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+    assert harness.get_relation_data(peer_rel_id, new_unit) == {"stanza": stanza_name}
 
     # Test when the "init-pgbackrest" flag was removed from the application relation databag
     # and this is the unit that has the stanza name in the unit relation databag.
     with harness.hooks_disabled():
         harness.update_relation_data(peer_rel_id, harness.charm.unit.name, {"stanza": stanza_name})
     harness.charm.backup.coordinate_stanza_fields()
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, harness.charm.app),
-        {"stanza": stanza_name},
-    )
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, new_unit), {"stanza": stanza_name})
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {"stanza": stanza_name}
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+    assert harness.get_relation_data(peer_rel_id, new_unit) == {"stanza": stanza_name}
 
     # Test when the unit is not the leader.
     with harness.hooks_disabled():
         harness.set_leader(False)
         harness.update_relation_data(peer_rel_id, harness.charm.unit.name, {"stanza": stanza_name})
     harness.charm.backup.coordinate_stanza_fields()
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, harness.charm.app),
-        {"stanza": stanza_name},
-    )
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, new_unit), {"stanza": stanza_name})
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {"stanza": stanza_name}
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
+    assert harness.get_relation_data(peer_rel_id, new_unit) == {"stanza": stanza_name}
 
 
 def test_is_primary_pgbackrest_service_running(harness):
@@ -1019,20 +956,20 @@ def test_is_primary_pgbackrest_service_running(harness):
         # Test when the pgBackRest fails to contact the primary server.
         _get_primary.side_effect = None
         _execute_command.return_value = (1, "", "fake stderr")
-        tc.assertFalse(harness.charm.backup._is_primary_pgbackrest_service_running)
+        assert not harness.charm.backup._is_primary_pgbackrest_service_running
         _execute_command.assert_called_once()
 
         # Test when the endpoint is not generated.
         _execute_command.reset_mock()
         _primary_endpoint.return_value = None
-        tc.assertFalse(harness.charm.backup._is_primary_pgbackrest_service_running)
+        assert not harness.charm.backup._is_primary_pgbackrest_service_running
         _execute_command.assert_not_called()
 
         # Test when the pgBackRest succeeds on contacting the primary server.
         _execute_command.reset_mock()
         _execute_command.return_value = (0, "fake stdout", "")
         _primary_endpoint.return_value = "fake_endpoint"
-        tc.assertTrue(harness.charm.backup._is_primary_pgbackrest_service_running)
+        assert harness.charm.backup._is_primary_pgbackrest_service_running
         _execute_command.assert_called_once()
 
 
@@ -1119,13 +1056,12 @@ def test_on_s3_credential_changed(harness):
             relation=harness.model.get_relation(S3_PARAMETERS_RELATION, s3_rel_id)
         )
         _render_pgbackrest_conf_file.assert_called_once()
-        tc.assertNotIn(
-            "require-change-bucket-after-restore",
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
+        assert "require-change-bucket-after-restore" not in harness.get_relation_data(
+            peer_rel_id, harness.charm.app
         )
         _is_primary.assert_called_once()
         _create_bucket_if_not_exists.assert_not_called()
-        tc.assertIsInstance(harness.charm.unit.status, ActiveStatus)
+        assert isinstance(harness.charm.unit.status, ActiveStatus)
         _can_use_s3_repository.assert_not_called()
         _initialise_stanza.assert_not_called()
 
@@ -1155,16 +1091,16 @@ def test_on_s3_credential_changed(harness):
                 relation=harness.model.get_relation(S3_PARAMETERS_RELATION, s3_rel_id)
             )
             _render_pgbackrest_conf_file.assert_called_once()
-            tc.assertEqual(
+            assert (
                 harness.get_relation_data(peer_rel_id, harness.charm.app)[
                     "require-change-bucket-after-restore"
-                ],
-                "True",
+                ]
+                == "True"
             )
             _create_bucket_if_not_exists.assert_called_once()
-            tc.assertIsInstance(harness.charm.unit.status, BlockedStatus)
-            tc.assertEqual(
-                harness.charm.unit.status.message, FAILED_TO_ACCESS_CREATE_BUCKET_ERROR_MESSAGE
+            assert isinstance(harness.charm.unit.status, BlockedStatus)
+            assert (
+                harness.charm.unit.status.message == FAILED_TO_ACCESS_CREATE_BUCKET_ERROR_MESSAGE
             )
             _can_use_s3_repository.assert_not_called()
             _initialise_stanza.assert_not_called()
@@ -1176,8 +1112,8 @@ def test_on_s3_credential_changed(harness):
         harness.charm.backup.s3_client.on.credentials_changed.emit(
             relation=harness.model.get_relation(S3_PARAMETERS_RELATION, s3_rel_id)
         )
-        tc.assertIsInstance(harness.charm.unit.status, BlockedStatus)
-        tc.assertEqual(harness.charm.unit.status.message, "fake validation message")
+        assert isinstance(harness.charm.unit.status, BlockedStatus)
+        assert harness.charm.unit.status.message == "fake validation message"
         _create_bucket_if_not_exists.assert_called_once()
         _can_use_s3_repository.assert_called_once()
         _initialise_stanza.assert_not_called()
@@ -1197,12 +1133,12 @@ def test_on_s3_credential_gone(harness):
     # Test that unrelated blocks will remain
     harness.charm.unit.status = BlockedStatus("test block")
     harness.charm.backup._on_s3_credential_gone(None)
-    tc.assertIsInstance(harness.charm.unit.status, BlockedStatus)
+    assert isinstance(harness.charm.unit.status, BlockedStatus)
 
     # Test that s3 related blocks will be cleared
     harness.charm.unit.status = BlockedStatus(ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE)
     harness.charm.backup._on_s3_credential_gone(None)
-    tc.assertIsInstance(harness.charm.unit.status, ActiveStatus)
+    assert isinstance(harness.charm.unit.status, ActiveStatus)
 
     # Test removal of relation data when the unit is not the leader.
     with harness.hooks_disabled():
@@ -1217,11 +1153,11 @@ def test_on_s3_credential_gone(harness):
             {"stanza": "test-stanza", "init-pgbackrest": "True"},
         )
     harness.charm.backup._on_s3_credential_gone(None)
-    tc.assertEqual(
-        harness.get_relation_data(peer_rel_id, harness.charm.app),
-        {"stanza": "test-stanza", "init-pgbackrest": "True"},
-    )
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+        "stanza": "test-stanza",
+        "init-pgbackrest": "True",
+    }
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
 
     # Test removal of relation data when the unit is the leader.
     with harness.hooks_disabled():
@@ -1232,8 +1168,8 @@ def test_on_s3_credential_gone(harness):
             {"stanza": "test-stanza", "init-pgbackrest": "True"},
         )
     harness.charm.backup._on_s3_credential_gone(None)
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
-    tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.unit), {})
+    assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+    assert harness.get_relation_data(peer_rel_id, harness.charm.unit) == {}
 
 
 def test_on_create_backup_action(harness):
@@ -1391,7 +1327,7 @@ def test_on_create_backup_action(harness):
                 mock_s3_parameters,
             ),
         ])
-        tc.assertEqual(_change_connectivity_to_database.call_count, 2)
+        assert _change_connectivity_to_database.call_count == 2
         mock_event.fail.assert_not_called()
         mock_event.set_results.assert_called_once_with({"backup-status": "backup created"})
 
@@ -1473,7 +1409,7 @@ def test_on_restore_action(harness):
         _start_patroni.assert_not_called()
         mock_event.fail.assert_not_called()
         mock_event.set_results.assert_not_called()
-        tc.assertNotIsInstance(harness.charm.unit.status, MaintenanceStatus)
+        assert not isinstance(harness.charm.unit.status, MaintenanceStatus)
 
         # Test when the user provides an invalid backup id.
         mock_event.params = {"backup-id": "2023-01-01T10:00:00Z"}
@@ -1491,7 +1427,7 @@ def test_on_restore_action(harness):
         _update_config.assert_not_called()
         _start_patroni.assert_not_called()
         mock_event.set_results.assert_not_called()
-        tc.assertNotIsInstance(harness.charm.unit.status, MaintenanceStatus)
+        assert not isinstance(harness.charm.unit.status, MaintenanceStatus)
 
         # Test when the charm fails to stop the workload.
         mock_event.reset_mock()
@@ -1526,16 +1462,13 @@ def test_on_restore_action(harness):
         _empty_data_files.return_value = True
         _execute_command.return_value = (1, "", "fake stderr")
         _fetch_backup_from_id.return_value = "20230101-090000F"
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
         harness.charm.backup._on_restore_action(mock_event)
-        tc.assertEqual(
-            harness.get_relation_data(peer_rel_id, harness.charm.app),
-            {
-                "restoring-backup": "20230101-090000F",
-                "restore-stanza": f"{harness.charm.model.name}.{harness.charm.cluster_name}",
-                "require-change-bucket-after-restore": "True",
-            },
-        )
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "restoring-backup": "20230101-090000F",
+            "restore-stanza": f"{harness.charm.model.name}.{harness.charm.cluster_name}",
+            "require-change-bucket-after-restore": "True",
+        }
         _execute_command.assert_called_once_with(
             [
                 "charmed-postgresql.patronictl",
@@ -1572,13 +1505,13 @@ def test_pre_restore_checks(harness):
         # Test when S3 parameters are not ok.
         mock_event = MagicMock(params={})
         _are_backup_settings_ok.return_value = (False, "fake error message")
-        tc.assertEqual(harness.charm.backup._pre_restore_checks(mock_event), False)
+        assert not harness.charm.backup._pre_restore_checks(mock_event)
         mock_event.fail.assert_called_once()
 
         # Test when no backup id is provided.
         mock_event.reset_mock()
         _are_backup_settings_ok.return_value = (True, None)
-        tc.assertEqual(harness.charm.backup._pre_restore_checks(mock_event), False)
+        assert not harness.charm.backup._pre_restore_checks(mock_event)
         mock_event.fail.assert_called_once()
 
         # Test when the unit is in a blocked state that is not recoverable by changing
@@ -1586,7 +1519,7 @@ def test_pre_restore_checks(harness):
         mock_event.reset_mock()
         mock_event.params = {"backup-id": "2023-01-01T09:00:00Z"}
         harness.charm.unit.status = BlockedStatus("fake blocked state")
-        tc.assertEqual(harness.charm.backup._pre_restore_checks(mock_event), False)
+        assert not harness.charm.backup._pre_restore_checks(mock_event)
         mock_event.fail.assert_called_once()
 
         # Test when the unit is in a blocked state that is recoverable by changing S3 parameters,
@@ -1594,20 +1527,20 @@ def test_pre_restore_checks(harness):
         mock_event.reset_mock()
         harness.charm.unit.status = BlockedStatus(ANOTHER_CLUSTER_REPOSITORY_ERROR_MESSAGE)
         _planned_units.return_value = 2
-        tc.assertEqual(harness.charm.backup._pre_restore_checks(mock_event), False)
+        assert not harness.charm.backup._pre_restore_checks(mock_event)
         mock_event.fail.assert_called_once()
 
         # Test when the cluster has only one unit, but it's not the leader yet.
         mock_event.reset_mock()
         _planned_units.return_value = 1
-        tc.assertEqual(harness.charm.backup._pre_restore_checks(mock_event), False)
+        assert not harness.charm.backup._pre_restore_checks(mock_event)
         mock_event.fail.assert_called_once()
 
         # Test when everything is ok to run a restore.
         mock_event.reset_mock()
         with harness.hooks_disabled():
             harness.set_leader()
-        tc.assertEqual(harness.charm.backup._pre_restore_checks(mock_event), True)
+        assert harness.charm.backup._pre_restore_checks(mock_event)
         mock_event.fail.assert_not_called()
 
 
@@ -1684,7 +1617,7 @@ def test_render_pgbackrest_conf_file(harness, tls_ca_chain_filename):
             harness.charm.backup._render_pgbackrest_conf_file()
 
         # Check the template is opened read-only in the call to open.
-        tc.assertEqual(mock.call_args_list[0][0], ("templates/pgbackrest.conf.j2", "r"))
+        assert mock.call_args_list[0][0] == ("templates/pgbackrest.conf.j2", "r")
 
         # Ensure the correct rendered template is sent to _render_file method.
         calls = [
@@ -1714,7 +1647,7 @@ def test_restart_database(harness):
         harness.charm.backup._restart_database()
 
         # Assert that the backup id is not in the application relation databag anymore.
-        tc.assertEqual(harness.get_relation_data(peer_rel_id, harness.charm.app), {})
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
 
         _update_config.assert_called_once()
         _start_patroni.assert_called_once()
@@ -1726,9 +1659,9 @@ def test_retrieve_s3_parameters(harness):
     ) as _get_s3_connection_info:
         # Test when there are missing S3 parameters.
         _get_s3_connection_info.return_value = {}
-        tc.assertEqual(
-            harness.charm.backup._retrieve_s3_parameters(),
-            ({}, ["bucket", "access-key", "secret-key"]),
+        assert harness.charm.backup._retrieve_s3_parameters() == (
+            {},
+            ["bucket", "access-key", "secret-key"],
         )
 
         # Test when only the required parameters are provided.
@@ -1737,21 +1670,18 @@ def test_retrieve_s3_parameters(harness):
             "access-key": "test-access-key",
             "secret-key": "test-secret-key",
         }
-        tc.assertEqual(
-            harness.charm.backup._retrieve_s3_parameters(),
-            (
-                {
-                    "access-key": "test-access-key",
-                    "bucket": "test-bucket",
-                    "delete-older-than-days": "9999999",
-                    "endpoint": "https://s3.amazonaws.com",
-                    "path": "/",
-                    "region": None,
-                    "s3-uri-style": "host",
-                    "secret-key": "test-secret-key",
-                },
-                [],
-            ),
+        assert harness.charm.backup._retrieve_s3_parameters() == (
+            {
+                "access-key": "test-access-key",
+                "bucket": "test-bucket",
+                "delete-older-than-days": "9999999",
+                "endpoint": "https://s3.amazonaws.com",
+                "path": "/",
+                "region": None,
+                "s3-uri-style": "host",
+                "secret-key": "test-secret-key",
+            },
+            [],
         )
 
         # Test when all parameters are provided.
@@ -1765,21 +1695,18 @@ def test_retrieve_s3_parameters(harness):
             "s3-uri-style": " path ",
             "delete-older-than-days": "30",
         }
-        tc.assertEqual(
-            harness.charm.backup._retrieve_s3_parameters(),
-            (
-                {
-                    "access-key": "test-access-key",
-                    "bucket": "test-bucket",
-                    "endpoint": "https://storage.googleapis.com",
-                    "path": "/test-path",
-                    "region": "us-east-1",
-                    "s3-uri-style": "path",
-                    "secret-key": "test-secret-key",
-                    "delete-older-than-days": "30",
-                },
-                [],
-            ),
+        assert harness.charm.backup._retrieve_s3_parameters() == (
+            {
+                "access-key": "test-access-key",
+                "bucket": "test-bucket",
+                "endpoint": "https://storage.googleapis.com",
+                "path": "/test-path",
+                "region": "us-east-1",
+                "s3-uri-style": "path",
+                "secret-key": "test-secret-key",
+                "delete-older-than-days": "30",
+            },
+            [],
         )
 
 
@@ -1809,30 +1736,21 @@ def test_start_stop_pgbackrest_service(harness):
         restart = MagicMock()
         stop = MagicMock()
         _snap_cache.return_value = {"charmed-postgresql": MagicMock(restart=restart, stop=stop)}
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            True,
-        )
+        assert harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_not_called()
         restart.assert_not_called()
 
         # Test when it was not possible to render the pgBackRest configuration file.
         _are_backup_settings_ok.return_value = (True, None)
         _render_pgbackrest_conf_file.return_value = False
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            False,
-        )
+        assert not harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_not_called()
         restart.assert_not_called()
 
         # Test when TLS is not enabled (should stop the service).
         _render_pgbackrest_conf_file.return_value = True
         _is_tls_enabled.return_value = False
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            True,
-        )
+        assert harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_called_once()
         restart.assert_not_called()
 
@@ -1840,10 +1758,7 @@ def test_start_stop_pgbackrest_service(harness):
         stop.reset_mock()
         _is_tls_enabled.return_value = True
         _peer_members_ips.return_value = []
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            True,
-        )
+        assert harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_called_once()
         restart.assert_not_called()
 
@@ -1852,19 +1767,13 @@ def test_start_stop_pgbackrest_service(harness):
         _peer_members_ips.return_value = ["1.1.1.1"]
         _is_primary.return_value = False
         _is_primary_pgbackrest_service_running.return_value = False
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            False,
-        )
+        assert not harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_not_called()
         restart.assert_not_called()
 
         # Test when the service has already started in the primary.
         _is_primary_pgbackrest_service_running.return_value = True
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            True,
-        )
+        assert harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_not_called()
         restart.assert_called_once()
 
@@ -1872,10 +1781,7 @@ def test_start_stop_pgbackrest_service(harness):
         restart.reset_mock()
         _is_primary.return_value = True
         _is_primary_pgbackrest_service_running.return_value = False
-        tc.assertEqual(
-            harness.charm.backup.start_stop_pgbackrest_service(),
-            True,
-        )
+        assert harness.charm.backup.start_stop_pgbackrest_service()
         stop.assert_not_called()
         restart.assert_called_once()
 
@@ -1911,10 +1817,7 @@ def test_upload_content_to_s3(harness, tls_ca_chain_filename):
         _resource.side_effect = ValueError
         _construct_endpoint.return_value = "https://s3.us-east-1.amazonaws.com"
         _named_temporary_file.return_value.__enter__.return_value.name = "/tmp/test-file"
-        tc.assertEqual(
-            harness.charm.backup._upload_content_to_s3(content, s3_path, s3_parameters),
-            False,
-        )
+        assert not harness.charm.backup._upload_content_to_s3(content, s3_path, s3_parameters)
         _resource.assert_called_once_with(
             "s3",
             endpoint_url="https://s3.us-east-1.amazonaws.com",
@@ -1926,10 +1829,7 @@ def test_upload_content_to_s3(harness, tls_ca_chain_filename):
         _resource.reset_mock()
         _resource.side_effect = None
         upload_file.side_effect = S3UploadFailedError
-        tc.assertEqual(
-            harness.charm.backup._upload_content_to_s3(content, s3_path, s3_parameters),
-            False,
-        )
+        assert not harness.charm.backup._upload_content_to_s3(content, s3_path, s3_parameters)
         _resource.assert_called_once_with(
             "s3",
             endpoint_url="https://s3.us-east-1.amazonaws.com",
@@ -1943,10 +1843,7 @@ def test_upload_content_to_s3(harness, tls_ca_chain_filename):
         _named_temporary_file.reset_mock()
         upload_file.reset_mock()
         upload_file.side_effect = None
-        tc.assertEqual(
-            harness.charm.backup._upload_content_to_s3(content, s3_path, s3_parameters),
-            True,
-        )
+        assert harness.charm.backup._upload_content_to_s3(content, s3_path, s3_parameters)
         _resource.assert_called_once_with(
             "s3",
             endpoint_url="https://s3.us-east-1.amazonaws.com",
diff --git a/tests/unit/test_charm.py b/tests/unit/test_charm.py
index 5cb0709891..9f4dd50535 100644
--- a/tests/unit/test_charm.py
+++ b/tests/unit/test_charm.py
@@ -5,7 +5,6 @@
 import logging
 import platform
 import subprocess
-from unittest import TestCase
 from unittest.mock import MagicMock, Mock, PropertyMock, call, mock_open, patch, sentinel
 
 import psycopg2
@@ -42,7 +41,6 @@
 CREATE_CLUSTER_CONF_PATH = "/etc/postgresql-common/createcluster.d/pgcharm.conf"
 
 # used for assert functions
-tc = TestCase()
 
 
 @pytest.fixture(autouse=True)
@@ -2398,7 +2396,7 @@ def test_set_primary_status_message(harness, is_leader):
             if is_leader
             else databag_containing_restore_data
         )
-        tc.assertIsInstance(harness.charm.unit.status, BlockedStatus)
+        assert isinstance(harness.charm.unit.status, BlockedStatus)
 
         # Test other scenarios.
         with harness.hooks_disabled():
@@ -2431,28 +2429,28 @@ def test_set_primary_status_message(harness, is_leader):
                     _is_standby_leader.side_effect = values[1]
                     _is_standby_leader.return_value = None
                     harness.charm._set_primary_status_message()
-                    tc.assertIsInstance(harness.charm.unit.status, MaintenanceStatus)
+                    assert isinstance(harness.charm.unit.status, MaintenanceStatus)
                 else:
                     _is_standby_leader.side_effect = None
                     _is_standby_leader.return_value = values[1]
                     harness.charm._set_primary_status_message()
-                    tc.assertIsInstance(
+                    assert isinstance(
                         harness.charm.unit.status,
                         ActiveStatus
                         if values[0] == harness.charm.unit.name or values[1] or values[2]
                         else MaintenanceStatus,
                     )
-                    tc.assertEqual(
-                        harness.charm.unit.status.message,
+                    status = (
                         "Primary"
                         if values[0] == harness.charm.unit.name
-                        else ("Standby" if values[1] else ("" if values[2] else "fake status")),
+                        else ("Standby" if values[1] else "" if values[2] else "fake status")
                     )
+                    assert harness.charm.unit.status.message == status
             else:
                 _get_primary.side_effect = values[0]
                 _get_primary.return_value = None
                 harness.charm._set_primary_status_message()
-                tc.assertIsInstance(harness.charm.unit.status, MaintenanceStatus)
+                assert isinstance(harness.charm.unit.status, MaintenanceStatus)
 
 
 def test_override_patroni_restart_condition(harness):
diff --git a/tests/unit/test_cluster.py b/tests/unit/test_cluster.py
index 370f47c147..aa95b3bc8c 100644
--- a/tests/unit/test_cluster.py
+++ b/tests/unit/test_cluster.py
@@ -1,7 +1,6 @@
 # Copyright 2021 Canonical Ltd.
 # See LICENSE file for licensing details.
 
-from unittest import TestCase
 from unittest.mock import MagicMock, Mock, PropertyMock, mock_open, patch, sentinel
 
 import pytest
@@ -25,9 +24,6 @@
 PATRONI_SERVICE = "patroni"
 CREATE_CLUSTER_CONF_PATH = "/var/snap/charmed-postgresql/current/etc/postgresql/postgresql.conf"
 
-# used for assert functions
-tc = TestCase()
-
 
 # This method will be used by the mock to replace requests.get
 def mocked_requests_get(*args, **kwargs):
@@ -92,7 +88,7 @@ def test_get_alternative_patroni_url(peers_ips, patroni):
 
     # Test the first URL that is returned (it should have the current unit IP).
     url = patroni._get_alternative_patroni_url(attempt)
-    tc.assertEqual(url, f"http://{patroni.unit_ip}:8008")
+    assert url == f"http://{patroni.unit_ip}:8008"
 
     # Test returning the other servers URLs.
     for attempt_number in range(attempt.retry_state.attempt_number + 1, len(peers_ips) + 2):
@@ -108,8 +104,9 @@ def test_get_member_ip(peers_ips, patroni):
     ):
         # Test error on trying to get the member IP.
         _get_alternative_patroni_url.side_effect = "http://server2"
-        with tc.assertRaises(tenacity.RetryError):
+        with pytest.raises(tenacity.RetryError):
             patroni.get_member_ip(patroni.member_name)
+            assert False
 
         # Test using an alternative Patroni URL.
         _get_alternative_patroni_url.side_effect = [
@@ -118,17 +115,17 @@ def test_get_member_ip(peers_ips, patroni):
             "http://server1",
         ]
         ip = patroni.get_member_ip(patroni.member_name)
-        tc.assertEqual(ip, "1.1.1.1")
+        assert ip == "1.1.1.1"
 
         # Test using the current Patroni URL.
         _get_alternative_patroni_url.side_effect = ["http://server1"]
         ip = patroni.get_member_ip(patroni.member_name)
-        tc.assertEqual(ip, "1.1.1.1")
+        assert ip == "1.1.1.1"
 
         # Test when not having that specific member in the cluster.
         _get_alternative_patroni_url.side_effect = ["http://server1"]
         ip = patroni.get_member_ip("other-member-name")
-        tc.assertIsNone(ip)
+        assert ip is None
 
 
 def test_get_patroni_health(peers_ips, patroni):
@@ -145,12 +142,13 @@ def test_get_patroni_health(peers_ips, patroni):
         _stop_after_delay.assert_called_once_with(60)
         _wait_fixed.assert_called_once_with(7)
 
-        tc.assertEqual(health, {"state": "running"})
+        assert health == {"state": "running"}
 
         # Test when the Patroni API is not reachable.
         _patroni_url.return_value = "http://server2"
-        with tc.assertRaises(tenacity.RetryError):
+        with pytest.raises(tenacity.RetryError):
             patroni.get_patroni_health()
+            assert False
 
 
 def test_get_postgresql_version(peers_ips, patroni):
@@ -163,7 +161,7 @@ def test_get_postgresql_version(peers_ips, patroni):
         ]
         version = patroni.get_postgresql_version()
 
-        tc.assertEqual(version, "14.0")
+        assert version == "14.0"
         _snap_client.assert_called_once_with()
         _get_installed_snaps.assert_called_once_with()
 
@@ -175,8 +173,9 @@ def test_get_primary(peers_ips, patroni):
     ):
         # Test error on trying to get the member IP.
         _get_alternative_patroni_url.side_effect = "http://server2"
-        with tc.assertRaises(tenacity.RetryError):
+        with pytest.raises(tenacity.RetryError):
             patroni.get_primary(patroni.member_name)
+            assert False
 
         # Test using an alternative Patroni URL.
         _get_alternative_patroni_url.side_effect = [
@@ -185,17 +184,17 @@ def test_get_primary(peers_ips, patroni):
             "http://server1",
         ]
         primary = patroni.get_primary()
-        tc.assertEqual(primary, "postgresql-0")
+        assert primary == "postgresql-0"
 
         # Test using the current Patroni URL.
         _get_alternative_patroni_url.side_effect = ["http://server1"]
         primary = patroni.get_primary()
-        tc.assertEqual(primary, "postgresql-0")
+        assert primary == "postgresql-0"
 
         # Test requesting the primary in the unit name pattern.
         _get_alternative_patroni_url.side_effect = ["http://server1"]
         primary = patroni.get_primary(unit_name_pattern=True)
-        tc.assertEqual(primary, "postgresql/0")
+        assert primary == "postgresql/0"
 
 
 def test_is_creating_backup(peers_ips, patroni):
@@ -208,13 +207,13 @@ def test_is_creating_backup(peers_ips, patroni):
                 {"name": "postgresql-1", "tags": {"is_creating_backup": True}},
             ]
         }
-        tc.assertTrue(patroni.is_creating_backup)
+        assert patroni.is_creating_backup
 
         # Test when no member is creating a backup.
         response.json.return_value = {
             "members": [{"name": "postgresql-0"}, {"name": "postgresql-1"}]
         }
-        tc.assertFalse(patroni.is_creating_backup)
+        assert not patroni.is_creating_backup
 
 
 def test_is_replication_healthy(peers_ips, patroni):
@@ -245,15 +244,15 @@ def test_is_member_isolated(peers_ips, patroni):
     ):
         # Test when it wasn't possible to connect to the Patroni API.
         _patroni_url.return_value = "http://server3"
-        tc.assertFalse(patroni.is_member_isolated)
+        assert not patroni.is_member_isolated
 
         # Test when the member isn't isolated from the cluster.
         _patroni_url.return_value = "http://server1"
-        tc.assertFalse(patroni.is_member_isolated)
+        assert not patroni.is_member_isolated
 
         # Test when the member is isolated from the cluster.
         _patroni_url.return_value = "http://server4"
-        tc.assertTrue(patroni.is_member_isolated)
+        assert patroni.is_member_isolated
 
 
 def test_render_file(peers_ips, patroni):
@@ -277,7 +276,7 @@ def test_render_file(peers_ips, patroni):
             patroni.render_file(filename, "rendered-content", 0o640)
 
         # Check the rendered file is opened with "w+" mode.
-        tc.assertEqual(mock.call_args_list[0][0], (filename, "w+"))
+        assert mock.call_args_list[0][0] == (filename, "w+")
         # Ensure that the correct user is lookup up.
         _pwnam.assert_called_with("snap_daemon")
         # Ensure the file is chmod'd correctly.
@@ -342,7 +341,7 @@ def test_render_patroni_yml_file(peers_ips, patroni):
             patroni.render_patroni_yml_file()
 
         # Check the template is opened read-only in the call to open.
-        tc.assertEqual(mock.call_args_list[0][0], ("templates/patroni.yml.j2", "r"))
+        assert mock.call_args_list[0][0] == ("templates/patroni.yml.j2", "r")
         # Ensure the correct rendered template is sent to _render_file method.
         _render_file.assert_called_once_with(
             "/var/snap/charmed-postgresql/current/etc/patroni/patroni.yaml",
@@ -457,8 +456,9 @@ def test_update_synchronous_node_count(peers_ips, patroni):
 
         # Test when the request fails.
         response.status_code = 500
-        with tc.assertRaises(RetryError):
+        with pytest.raises(RetryError):
             patroni.update_synchronous_node_count()
+            assert False
 
 
 def test_configure_patroni_on_unit(peers_ips, patroni):
@@ -626,8 +626,9 @@ def test_get_patroni_restart_condition(patroni):
 
         # Test when there is no restart condition set.
         _open.return_value.__enter__.return_value.read.return_value = ""
-        with tc.assertRaises(RuntimeError):
+        with pytest.raises(RuntimeError):
             patroni.get_patroni_restart_condition()
+            assert False
 
 
 @pytest.mark.parametrize("new_restart_condition", ["on-success", "on-failure"])