diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 821f2c434..c822150c3 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -1,114 +1,97 @@
+# Copyright 2022 Canonical Ltd.
+# See LICENSE file for licensing details.
 name: Tests
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 on:
-  workflow_call:
   pull_request:
+  schedule:
+    - cron: '53 0 * * *' # Daily at 00:53 UTC
+  # Triggered on push to branch "main" by .github/workflows/release.yaml
+  workflow_call:
 
 jobs:
   lint:
     name: Lint
     runs-on: ubuntu-22.04
+    timeout-minutes: 5
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-      - name: Install dependencies
+      - name: Install tox
+        # TODO: Consider replacing with custom image on self-hosted runner OR pinning version
         run: python3 -m pip install tox
       - name: Run linters
-        run: tox -e lint
+        run: tox run -e lint
 
   unit-test:
     name: Unit tests
     runs-on: ubuntu-22.04
+    timeout-minutes: 5
     needs:
       - lint
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-      - name: Install dependencies
-        run: python -m pip install tox
+      - name: Install tox
+        # TODO: Consider replacing with custom image on self-hosted runner OR pinning version
+        run: python3 -m pip install tox
       - name: Run tests
-        run: tox -e unit
+        run: tox run -e unit
 
-  integration-test-lxd-charm:
-    name: Integration tests for the charm (lxd)
-    runs-on: ubuntu-22.04
-    needs:
-      - unit-test
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Setup operator environment
-        uses: charmed-kubernetes/actions-operator@main
-        with:
-          provider: lxd
-      - name: Run integration tests
-        run: |
-          # set sysctl values in case the cloudinit-userdata not applied
-          sudo sysctl -w vm.max_map_count=262144
-          sudo sysctl -w vm.swappiness=0
-          sudo sysctl -w net.ipv4.tcp_retries2=5
+  build:
+    name: Build charms
+    uses: canonical/data-platform-workflows/.github/workflows/build_charms_with_cache.yaml@v2
 
-          tox -e charm-integration
-
-  integration-test-lxd-tls:
-    name: Integration tests for TLS (lxd)
-    runs-on: ubuntu-22.04
-    needs:
-      - unit-test
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Setup operator environment
-        uses: charmed-kubernetes/actions-operator@main
-        with:
-          provider: lxd
-      - name: Run integration tests
-        run: |
-          # set sysctl values in case the cloudinit-userdata not applied
-          sudo sysctl -w vm.max_map_count=262144
-          sudo sysctl -w vm.swappiness=0
-          sudo sysctl -w net.ipv4.tcp_retries2=5
-
-          tox -e tls-integration
-
-# Commented due to failures because of HW related issues of the github runners:
-#  integration-test-lxd-ha:
-#    name: Integration tests for HA (lxd)
-#    runs-on: ubuntu-22.04
-#    needs:
-#      - unit-test
-#    steps:
-#      - name: Checkout
-#        uses: actions/checkout@v3
-#      - name: Setup operator environment
-#        uses: charmed-kubernetes/actions-operator@main
-#        with:
-#          provider: lxd
-#      - name: Run integration tests
-#        run: |
-#          # set sysctl values in case the cloudinit-userdata not applied
-#          sudo sysctl -w vm.max_map_count=262144
-#          sudo sysctl -w vm.swappiness=0
-#          sudo sysctl -w net.ipv4.tcp_retries2=5
-#
-#          tox -e ha-integration
-
-  integration-test-client-relation:
-    name: Integration tests for client relation
-    runs-on: ubuntu-22.04
+  integration-test:
+    strategy:
+      fail-fast: false
+      matrix:
+        tox-environments:
+          - charm-integration
+          - tls-integration
+#          - ha-integration
+          - client-integration
+    name: ${{ matrix.tox-environments }}
     needs:
       - lint
       - unit-test
+      - build
+    runs-on: ubuntu-latest
+    timeout-minutes: 120
     steps:
       - name: Checkout
         uses: actions/checkout@v3
       - name: Setup operator environment
+        # TODO: Replace with custom image on self-hosted runner
         uses: charmed-kubernetes/actions-operator@main
         with:
           provider: lxd
+      - name: Download packed charm(s)
+        uses: actions/download-artifact@v3
+        with:
+          name: ${{ needs.build.outputs.artifact-name }}
+      - name: Select tests
+        id: select-tests
+        run: |
+          if [ "${{ github.event_name }}" == "schedule" ]
+          then
+            echo Running unstable and stable tests
+            echo "mark_expression=" >> $GITHUB_OUTPUT
+          else
+            echo Skipping unstable tests
+            echo "mark_expression=not unstable" >> $GITHUB_OUTPUT
+          fi
       - name: Run integration tests
         run: |
           # set sysctl values in case the cloudinit-userdata not applied
           sudo sysctl -w vm.max_map_count=262144
           sudo sysctl -w vm.swappiness=0
           sudo sysctl -w net.ipv4.tcp_retries2=5
-          tox -e client-integration
+
+          tox run -e ${{ matrix.tox-environments }} -- -m '${{ steps.select-tests.outputs.mark_expression }}'
+        env:
+          CI_PACKED_CHARMS: ${{ needs.build.outputs.charms }}
diff --git a/.github/workflows/on_push.yaml b/.github/workflows/on_push.yaml
deleted file mode 100644
index 346065cdc..000000000
--- a/.github/workflows/on_push.yaml
+++ /dev/null
@@ -1,12 +0,0 @@
-name: Tests
-on:
-  push:
-    branches:
-      - main
-      - track/**
-      - feature/**
-
-jobs:
-  run-tests:
-    name: Run Tests
-    uses: ./.github/workflows/ci.yaml
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 240b39c42..9f5eaa792 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -9,6 +9,7 @@ jobs:
   lib-check:
     name: Check libraries
     runs-on: ubuntu-22.04
+    timeout-minutes: 5
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -29,6 +30,7 @@ jobs:
       - lib-check
       - ci-tests
     runs-on: ubuntu-22.04
+    timeout-minutes: 60
     steps:
       - name: Checkout
         uses: actions/checkout@v3
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 70c9c1b43..c1cfa3ab5 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -23,21 +23,21 @@ this operator.
 
 ## Developing
 
-You can use the environments created by `tox` for development:
+You can create an environment for development with `tox`:
 
 ```shell
-tox --notest -e unit
-source .tox/unit/bin/activate
+tox devenv -e integration
+source venv/bin/activate
 ```
 
 ### Testing
 
 ```shell
-tox -e fmt           # update your code according to linting rules
-tox -e lint          # code style
-tox -e unit          # unit tests
-tox -e integration   # integration tests
-tox                  # runs 'lint' and 'unit' environments
+tox run -e format        # update your code according to linting rules
+tox run -e lint          # code style
+tox run -e unit          # unit tests
+tox run -e integration   # integration tests
+tox                      # runs 'format', 'lint', and 'unit' environments
 ```
 
 ## Build charm
diff --git a/pyproject.toml b/pyproject.toml
index f4ed7e804..44aa33b16 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,12 +12,7 @@ show_missing = true
 minversion = "6.0"
 log_cli_level = "INFO"
 asyncio_mode = "auto"
-markers = [
-    "charm_tests",
-    "tls_tests",
-    "ha_tests",
-    "client_relation: integration tests that test modern client relations",
-]
+markers = ["unstable"]
 
 # Formatting tools configuration
 [tool.black]
diff --git a/tests/integration/conftest.py b/tests/integration/conftest.py
new file mode 100644
index 000000000..da132958d
--- /dev/null
+++ b/tests/integration/conftest.py
@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+# Copyright 2022 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+import json
+import os
+from pathlib import Path
+
+import pytest
+from pytest_operator.plugin import OpsTest
+
+
+@pytest.fixture(scope="module")
+def ops_test(ops_test: OpsTest) -> OpsTest:
+    if os.environ.get("CI") == "true":
+        # Running in GitHub Actions; skip build step
+        # (GitHub Actions uses a separate, cached build step. See .github/workflows/ci.yaml)
+        packed_charms = json.loads(os.environ["CI_PACKED_CHARMS"])
+
+        async def build_charm(charm_path, bases_index: int = None) -> Path:
+            for charm in packed_charms:
+                if Path(charm_path) == Path(charm["directory_path"]):
+                    if bases_index is None or bases_index == charm["bases_index"]:
+                        return charm["file_path"]
+            raise ValueError(f"Unable to find .charm file for {bases_index=} at {charm_path=}")
+
+        ops_test.build_charm = build_charm
+    return ops_test
diff --git a/tests/integration/ha/test_horizontal_scaling.py b/tests/integration/ha/test_horizontal_scaling.py
index b3c0840db..ced0e0e4d 100644
--- a/tests/integration/ha/test_horizontal_scaling.py
+++ b/tests/integration/ha/test_horizontal_scaling.py
@@ -33,7 +33,6 @@
 logger = logging.getLogger(__name__)
 
 
-@pytest.mark.ha_tests
 @pytest.mark.abort_on_fail
 @pytest.mark.skip_if_deployed
 async def test_build_and_deploy(ops_test: OpsTest) -> None:
@@ -65,7 +64,6 @@ async def test_build_and_deploy(ops_test: OpsTest) -> None:
     )
 
 
-@pytest.mark.ha_tests
 @pytest.mark.abort_on_fail
 async def test_horizontal_scale_up(ops_test: OpsTest) -> None:
     """Tests that new added units to the cluster are discoverable."""
@@ -92,7 +90,6 @@ async def test_horizontal_scale_up(ops_test: OpsTest) -> None:
     assert ClusterTopology.nodes_count_by_role(nodes)["cluster_manager"] == 3
 
 
-@pytest.mark.ha_tests
 @pytest.mark.abort_on_fail
 async def test_safe_scale_down_shards_realloc(ops_test: OpsTest) -> None:
     """Tests the shutdown of a node, and re-allocation of shards to a newly joined unit.
@@ -180,7 +177,6 @@ async def test_safe_scale_down_shards_realloc(ops_test: OpsTest) -> None:
     assert new_shards_per_node.get(-1, 0) == 0
 
 
-@pytest.mark.ha_tests
 @pytest.mark.abort_on_fail
 async def test_safe_scale_down_roles_reassigning(ops_test: OpsTest) -> None:
     """Tests the shutdown of a node with a role requiring the re-balance of the cluster roles.
diff --git a/tests/integration/relations/opensearch_provider/conftest.py b/tests/integration/relations/opensearch_provider/conftest.py
index 98aaba9f3..522cd3af7 100644
--- a/tests/integration/relations/opensearch_provider/conftest.py
+++ b/tests/integration/relations/opensearch_provider/conftest.py
@@ -6,7 +6,6 @@
 from pytest_operator.plugin import OpsTest
 
 
-@pytest.mark.abort_on_fail
 @pytest.fixture(scope="module")
 async def application_charm(ops_test: OpsTest):
     """Build the application charm."""
@@ -14,7 +13,6 @@ async def application_charm(ops_test: OpsTest):
     return await ops_test.build_charm(test_charm_path)
 
 
-@pytest.mark.abort_on_fail
 @pytest.fixture(scope="module")
 async def opensearch_charm(ops_test: OpsTest):
     """Build the opensearch charm."""
diff --git a/tests/integration/relations/opensearch_provider/test_opensearch_provider.py b/tests/integration/relations/opensearch_provider/test_opensearch_provider.py
index 00262b875..9fbdd442e 100644
--- a/tests/integration/relations/opensearch_provider/test_opensearch_provider.py
+++ b/tests/integration/relations/opensearch_provider/test_opensearch_provider.py
@@ -37,7 +37,6 @@
 
 
 @pytest.mark.abort_on_fail
-@pytest.mark.client_relation
 async def test_database_relation_with_charm_libraries(
     ops_test: OpsTest, application_charm, opensearch_charm
 ):
@@ -77,7 +76,6 @@ async def test_database_relation_with_charm_libraries(
     # )
 
 
-@pytest.mark.client_relation
 async def test_database_usage(ops_test: OpsTest):
     """Check we can update and delete things."""
     await run_request(
@@ -108,7 +106,6 @@ async def test_database_usage(ops_test: OpsTest):
     )
 
 
-@pytest.mark.client_relation
 async def test_database_bulk_usage(ops_test: OpsTest):
     """Check we can update and delete things using bulk api."""
     bulk_payload = """{ "index" : { "_index": "albums", "_id" : "2" } }
@@ -149,7 +146,6 @@ async def test_database_bulk_usage(ops_test: OpsTest):
     assert set(artists) == {"Herbie Hancock", "Lydian Collective", "Vulfpeck"}
 
 
-@pytest.mark.client_relation
 async def test_database_version(ops_test: OpsTest):
     """Check version is accurate."""
     run_version_request = await run_request(
@@ -170,7 +166,6 @@ async def test_database_version(ops_test: OpsTest):
     assert version == results.get("version", {}).get("number")
 
 
-@pytest.mark.client_relation
 async def test_multiple_relations(ops_test: OpsTest, application_charm):
     """Test that two different applications can connect to the database."""
     # Deploy secondary application.
@@ -198,7 +193,6 @@ async def test_multiple_relations(ops_test: OpsTest, application_charm):
         )
 
 
-@pytest.mark.client_relation
 async def test_relation_broken(ops_test: OpsTest):
     """Test that the user is removed when the relation is broken."""
     # Retrieve the relation user.
diff --git a/tests/integration/test_charm.py b/tests/integration/test_charm.py
index 93bed015d..9536413ce 100644
--- a/tests/integration/test_charm.py
+++ b/tests/integration/test_charm.py
@@ -26,7 +26,6 @@
 DEFAULT_NUM_UNITS = 2
 
 
-@pytest.mark.charm_tests
 @pytest.mark.abort_on_fail
 @pytest.mark.skip_if_deployed
 async def test_build_and_deploy(ops_test: OpsTest) -> None:
@@ -42,7 +41,6 @@ async def test_build_and_deploy(ops_test: OpsTest) -> None:
     await ops_test.model.wait_for_idle(wait_for_exact_units=DEFAULT_NUM_UNITS)
 
 
-@pytest.mark.charm_tests
 @pytest.mark.abort_on_fail
 async def test_status(ops_test: OpsTest) -> None:
     """Verifies that the application and unit are active."""
@@ -52,7 +50,6 @@ async def test_status(ops_test: OpsTest) -> None:
     assert len(ops_test.model.applications[APP_NAME].units) == DEFAULT_NUM_UNITS
 
 
-@pytest.mark.charm_tests
 @pytest.mark.abort_on_fail
 async def test_actions_get_admin_password(ops_test: OpsTest) -> None:
     """Test the retrieval of admin secrets."""
@@ -91,7 +88,6 @@ async def test_actions_get_admin_password(ops_test: OpsTest) -> None:
     assert result.status == "failed"
 
 
-@pytest.mark.charm_tests
 @pytest.mark.abort_on_fail
 async def test_actions_rotate_admin_password(ops_test: OpsTest) -> None:
     """Test the rotation and change of admin password."""
diff --git a/tests/integration/tls/test_tls.py b/tests/integration/tls/test_tls.py
index 3a1e963af..267f9bed9 100644
--- a/tests/integration/tls/test_tls.py
+++ b/tests/integration/tls/test_tls.py
@@ -27,7 +27,6 @@
 TLS_CERTIFICATES_APP_NAME = "tls-certificates-operator"
 
 
-@pytest.mark.tls_tests
 @pytest.mark.abort_on_fail
 @pytest.mark.skip_if_deployed
 async def test_build_and_deploy_active(ops_test: OpsTest) -> None:
@@ -57,7 +56,6 @@ async def test_build_and_deploy_active(ops_test: OpsTest) -> None:
     )
 
 
-@pytest.mark.tls_tests
 @pytest.mark.abort_on_fail
 async def test_security_index_initialised(ops_test: OpsTest) -> None:
     """Test that the security index is well initialised."""
@@ -66,7 +64,6 @@ async def test_security_index_initialised(ops_test: OpsTest) -> None:
     assert await check_security_index_initialised(ops_test, leader_unit_ip)
 
 
-@pytest.mark.tls_tests
 @pytest.mark.abort_on_fail
 async def test_tls_configured(ops_test: OpsTest) -> None:
     """Test that TLS is enabled when relating to the TLS Certificates Operator."""
@@ -74,7 +71,6 @@ async def test_tls_configured(ops_test: OpsTest) -> None:
         assert await check_unit_tls_configured(ops_test, unit_ip, unit_name)
 
 
-@pytest.mark.tls_tests
 @pytest.mark.abort_on_fail
 async def test_cluster_formation_after_tls(ops_test: OpsTest) -> None:
     """Test that the cluster formation is successful after TLS setup."""
diff --git a/tox.ini b/tox.ini
index 36826d917..cfa193307 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,27 +2,27 @@
 # See LICENSE file for licensing details.
 
 [tox]
-skipsdist=True
+no_package = True
 skip_missing_interpreters = True
-envlist = fmt, lint, unit
+env_list = format, lint, unit
 
 [vars]
-src_path = {toxinidir}/src/
-tst_path = {toxinidir}/tests/
-lib_path = {toxinidir}/lib/charms/opensearch/v0/
-all_path = {[vars]src_path} {[vars]lib_path} {[vars]tst_path}
+src_path = {tox_root}/src
+tests_path = {tox_root}/tests
+lib_path = {tox_root}/lib/charms/opensearch/v0
+all_path = {[vars]src_path} {[vars]lib_path} {[vars]tests_path}
 
 [testenv]
-setenv =
-  PYTHONPATH = {toxinidir}:{toxinidir}/lib:{[vars]src_path}
-  PYTHONBREAKPOINT=ipdb.set_trace
-  PY_COLORS=1
-passenv =
-  PYTHONPATH
-  CHARM_BUILD_DIR
-  MODEL_SETTINGS
+set_env =
+    PYTHONPATH = {tox_root}:{tox_root}/lib:{[vars]src_path}
+    PYTHONBREAKPOINT=ipdb.set_trace
+    PY_COLORS=1
+pass_env =
+    PYTHONPATH
+    CHARM_BUILD_DIR
+    MODEL_SETTINGS
 
-[testenv:fmt]
+[testenv:format]
 description = Apply coding style standards to code
 deps =
     black
@@ -45,9 +45,9 @@ deps =
     codespell
 commands =
     codespell {[vars]lib_path}
-    codespell {toxinidir} --skip {toxinidir}/.git --skip {toxinidir}/.tox \
-      --skip {toxinidir}/build --skip {toxinidir}/lib --skip {toxinidir}/venv \
-      --skip {toxinidir}/.mypy_cache --skip {toxinidir}/icon.svg
+    codespell {tox_root} --skip {tox_root}/.git --skip {tox_root}/.tox \
+      --skip {tox_root}/build --skip {tox_root}/lib --skip {tox_root}/venv \
+      --skip {tox_root}/.mypy_cache --skip {tox_root}/icon.svg
     # pflake8 wrapper supports config from pyproject.toml
     pflake8 {[vars]all_path}
     isort --check-only --diff {[vars]all_path}
@@ -59,63 +59,83 @@ deps =
     pytest
     pytest-asyncio
     coverage[toml]
-    -r{toxinidir}/requirements.txt
+    -r {tox_root}/requirements.txt
 commands =
     coverage run --source={[vars]src_path} --source={[vars]lib_path} \
-        -m pytest --ignore={[vars]tst_path}integration -v --tb native -s {posargs}
+        -m pytest -v --tb native -s {posargs} {[vars]tests_path}/unit
     coverage report
 
 [testenv:charm-integration]
 description = Run charm integration tests
+pass_env =
+    {[testenv]pass_env}
+    CI
+    CI_PACKED_CHARMS
 deps =
     pytest
     pytest-asyncio
     juju==2.9.38.1 # juju 3.0.0 has issues with retrieving action results
     pytest-operator
-    -r{toxinidir}/requirements.txt
+    -r {tox_root}/requirements.txt
 commands =
-    pytest -v --tb native --ignore={[vars]tst_path}unit --log-cli-level=INFO -s {posargs} -m charm_tests
+    pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/test_charm.py
 
 [testenv:tls-integration]
 description = Run TLS integration tests
+pass_env =
+    {[testenv]pass_env}
+    CI
+    CI_PACKED_CHARMS
 deps =
     pytest
     pytest-asyncio
     juju==2.9.38.1 # juju 3.0.0 has issues with retrieving action results
     pytest-operator
-    -r{toxinidir}/requirements.txt
+    -r {tox_root}/requirements.txt
 commands =
-    pytest -v --tb native --ignore={[vars]tst_path}unit --log-cli-level=INFO -s {posargs} -m tls_tests
+    pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/tls/test_tls.py
 
 [testenv:ha-integration]
 description = Run HA integration tests
+pass_env =
+    {[testenv]pass_env}
+    CI
+    CI_PACKED_CHARMS
 deps =
     pytest
     pytest-asyncio
     juju==2.9.38.1 # juju 3.0.0 has issues with retrieving action results
     pytest-operator
-    -r{toxinidir}/requirements.txt
+    -r {tox_root}/requirements.txt
 commands =
-    pytest -v --tb native --ignore={[vars]tst_path}unit --log-cli-level=INFO -s {posargs} -m ha_tests
+    pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/ha/test_horizontal_scaling.py
 
 [testenv:client-integration]
 description = Run client relation integration tests
+pass_env =
+    {[testenv]pass_env}
+    CI
+    CI_PACKED_CHARMS
 deps =
     pytest
     pytest-asyncio
     juju==2.9.38.1 # juju 3.0.0 has issues with retrieving action results
     pytest-operator
-    -r{toxinidir}/requirements.txt
+    -r {tox_root}/requirements.txt
 commands =
-    pytest -v --tb native --ignore={[vars]tst_path}unit --log-cli-level=INFO -s {posargs} -m client_relation
+    pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/relations/opensearch_provider/test_opensearch_provider.py
 
 [testenv:integration]
 description = Run all integration tests
+pass_env =
+    {[testenv]pass_env}
+    CI
+    CI_PACKED_CHARMS
 deps =
     pytest
     pytest-asyncio
     juju==2.9.38.1 # juju 3.0.0 has issues with retrieving action results
     pytest-operator
-    -r{toxinidir}/requirements.txt
+    -r {tox_root}/requirements.txt
 commands =
-    pytest -v --tb native --ignore={[vars]tst_path}unit --log-cli-level=INFO -s {posargs}
+    pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tests_path}/integration/