diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index a2a42687b1..5bb4b61c55 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -56,7 +56,7 @@ jobs:
         python-version: '3.10'
 
     - name: Run benchmarks
-      run: pytest --benchmark-only --benchmark-json benchmark.json
+      run: pytest --db-backend psql --benchmark-only --benchmark-json benchmark.json tests/
 
     - name: Store benchmark result
       uses: aiidateam/github-action-benchmark@v3
@@ -73,4 +73,4 @@ jobs:
         alert-threshold: 200%
         comment-on-alert: true
         fail-on-alert: false
-        alert-comment-cc-users: '@chrisjsewell,@giovannipizzi'
+        alert-comment-cc-users: '@giovannipizzi,@agoscinski,@GeigerJ2,@khsrali,@unkcpz'
diff --git a/.github/workflows/ci-code.yml b/.github/workflows/ci-code.yml
index b5f6aa424d..a8d0cb9a08 100644
--- a/.github/workflows/ci-code.yml
+++ b/.github/workflows/ci-code.yml
@@ -104,7 +104,7 @@ jobs:
         AIIDA_WARN_v3: 1
       # Python 3.12 has a performance regression when running with code coverage
       # so run code coverage only for python 3.9.
-      run: pytest tests -m 'not nightly' ${{ matrix.python-version == '3.9' && '--cov aiida' || '' }}
+      run: pytest --db-backend psql -m 'not nightly' tests/ ${{ matrix.python-version == '3.9' && '--cov aiida' || '' }}
 
     - name: Upload coverage report
       if: matrix.python-version == 3.9 && github.repository == 'aiidateam/aiida-core'
@@ -139,7 +139,7 @@ jobs:
     - name: Run test suite
       env:
         AIIDA_WARN_v3: 0
-      run: pytest -m 'presto'
+      run: pytest -m 'presto' tests/
 
 
   verdi:
diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index f88e4f8d72..84ed617125 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -104,19 +104,6 @@ jobs:
         rabbitmq-version: ['3.11', '3.12', '3.13']
 
     services:
-      postgres:
-        image: postgres:16
-        env:
-          POSTGRES_DB: test_aiida
-          POSTGRES_PASSWORD: ''
-          POSTGRES_HOST_AUTH_METHOD: trust
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
-        ports:
-        - 5432:5432
       rabbitmq:
         image: rabbitmq:${{ matrix.rabbitmq-version }}-management
         ports:
@@ -132,9 +119,6 @@ jobs:
       with:
         python-version: '3.11'
 
-    - name: Install system dependencies
-      run: sudo apt update && sudo apt install postgresql
-
     - name: Setup SSH on localhost
       run: .github/workflows/setup_ssh.sh
 
@@ -145,7 +129,7 @@ jobs:
       id: tests
       env:
         AIIDA_WARN_v3: 0
-      run: pytest -s -m 'requires_rmq'
+      run: pytest -s --db-backend sqlite -m 'requires_rmq' tests/
 
     - name: Slack notification
       # Always run this step (otherwise it would be skipped if any of the previous steps fail) but only if the
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index be1fbf7200..c47595baee 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -54,19 +54,6 @@ jobs:
     timeout-minutes: 30
 
     services:
-      postgres:
-        image: postgres:10
-        env:
-          POSTGRES_DB: test_aiida
-          POSTGRES_PASSWORD: ''
-          POSTGRES_HOST_AUTH_METHOD: trust
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
-        ports:
-        - 5432:5432
       rabbitmq:
         image: rabbitmq:3.8.14-management
         ports:
@@ -76,16 +63,11 @@ jobs:
     steps:
     - uses: actions/checkout@v4
 
-    - name: Install system dependencies
-      run: |
-        sudo apt update
-        sudo apt install postgresql graphviz
-
     - name: Install aiida-core
       uses: ./.github/actions/install-aiida-core
 
     - name: Run sub-set of test suite
-      run: pytest -s -k 'requires_rmq'
+      run: pytest -s -m requires_rmq --db-backend=sqlite tests/
 
   publish:
 
diff --git a/.github/workflows/test-install.yml b/.github/workflows/test-install.yml
index 57ea0778c0..d315a50691 100644
--- a/.github/workflows/test-install.yml
+++ b/.github/workflows/test-install.yml
@@ -229,7 +229,7 @@ jobs:
       env:
         AIIDA_TEST_PROFILE: test_aiida
         AIIDA_WARN_v3: 1
-      run: pytest tests -m 'not nightly'
+      run: pytest --db-backend psql tests -m 'not nightly' tests/
 
     - name: Freeze test environment
       run: pip freeze | sed '1d' | tee requirements-py-${{ matrix.python-version }}.txt
diff --git a/.github/workflows/tests_nightly.sh b/.github/workflows/tests_nightly.sh
index dc02958a99..ef7e0ced06 100755
--- a/.github/workflows/tests_nightly.sh
+++ b/.github/workflows/tests_nightly.sh
@@ -13,4 +13,4 @@ verdi -p test_aiida run ${SYSTEM_TESTS}/test_containerized_code.py
 bash ${SYSTEM_TESTS}/test_polish_workchains.sh
 verdi daemon stop
 
-AIIDA_TEST_PROFILE=test_aiida pytest tests -m 'nightly'
+AIIDA_TEST_PROFILE=test_aiida pytest --db-backend psql -m nightly tests/
\ No newline at end of file
diff --git a/tests/conftest.py b/tests/conftest.py
index 2166cc06c0..fb6780d966 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -22,6 +22,7 @@
 import types
 import typing as t
 import warnings
+from enum import Enum
 from pathlib import Path
 
 import click
@@ -37,7 +38,14 @@
 pytest_plugins = ['aiida.tools.pytest_fixtures', 'sphinx.testing.fixtures']
 
 
-def pytest_collection_modifyitems(items):
+class TestDbBackend(Enum):
+    """Options for the '--db-backend' CLI argument when running pytest."""
+
+    SQLITE = 'sqlite'
+    PSQL = 'psql'
+
+
+def pytest_collection_modifyitems(items, config):
     """Automatically generate markers for certain tests.
 
     Most notably, we add the 'presto' marker for all tests that
@@ -47,6 +55,14 @@ def pytest_collection_modifyitems(items):
     filepath_django = Path(__file__).parent / 'storage' / 'psql_dos' / 'migrations' / 'django_branch'
     filepath_sqla = Path(__file__).parent / 'storage' / 'psql_dos' / 'migrations' / 'sqlalchemy_branch'
 
+    # If the user requested the SQLite backend, automatically skip incompatible tests
+    if config.option.db_backend is TestDbBackend.SQLITE:
+        if config.option.markexpr != '':
+            # Don't overwrite markers that the user already provided via '-m ' cmdline argument
+            config.option.markexpr += ' and (not requires_psql)'
+        else:
+            config.option.markexpr = 'not requires_psql'
+
     for item in items:
         filepath_item = Path(item.fspath)
 
@@ -68,6 +84,30 @@ def pytest_collection_modifyitems(items):
             item.add_marker('presto')
 
 
+def db_backend_type(string):
+    """Conversion function for the custom '--db-backend' pytest CLI option
+
+    :param string: String provided by the user via CLI
+    :returns: DbBackend enum corresponding to user input string
+    """
+    try:
+        return TestDbBackend(string)
+    except ValueError:
+        msg = f"Invalid --db-backend option '{string}'\nMust be one of: {tuple(db.value for db in TestDbBackend)}"
+        raise pytest.UsageError(msg)
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        '--db-backend',
+        action='store',
+        default=TestDbBackend.SQLITE,
+        required=False,
+        help=f'Database backend to be used for tests {tuple(db.value for db in TestDbBackend)}',
+        type=db_backend_type,
+    )
+
+
 @pytest.fixture(scope='session')
 def aiida_profile(pytestconfig, aiida_config, aiida_profile_factory, config_psql_dos, config_sqlite_dos):
     """Create and load a profile with ``core.psql_dos`` as a storage backend and RabbitMQ as the broker.
@@ -77,18 +117,22 @@ def aiida_profile(pytestconfig, aiida_config, aiida_profile_factory, config_psql
     be run against the main storage backend, which is ``core.sqlite_dos``.
     """
     marker_opts = pytestconfig.getoption('-m')
+    db_backend = pytestconfig.getoption('--db-backend')
 
-    # By default we use RabbitMQ broker and psql_dos storage
+    # We use RabbitMQ broker by default unless 'presto' marker is specified
     broker = 'core.rabbitmq'
     if 'not requires_rmq' in marker_opts or 'presto' in marker_opts:
         broker = None
 
-    if 'not requires_psql' in marker_opts or 'presto' in marker_opts:
+    if db_backend is TestDbBackend.SQLITE:
         storage = 'core.sqlite_dos'
         config = config_sqlite_dos()
-    else:
+    elif db_backend is TestDbBackend.PSQL:
         storage = 'core.psql_dos'
         config = config_psql_dos()
+    else:
+        # This should be unreachable
+        raise ValueError(f'Invalid DB backend {db_backend}')
 
     with aiida_profile_factory(
         aiida_config, storage_backend=storage, storage_config=config, broker_backend=broker
diff --git a/tests/storage/psql_dos/conftest.py b/tests/storage/psql_dos/conftest.py
index 16136b8df9..c24db0ac72 100644
--- a/tests/storage/psql_dos/conftest.py
+++ b/tests/storage/psql_dos/conftest.py
@@ -13,17 +13,12 @@
 from aiida.common.exceptions import MissingConfigurationError
 from aiida.manage.configuration import get_config
 
+STORAGE_BACKEND_ENTRY_POINT = None
 try:
     if test_profile := os.environ.get('AIIDA_TEST_PROFILE'):
         STORAGE_BACKEND_ENTRY_POINT = get_config().get_profile(test_profile).storage_backend
-    # TODO: The else branch is wrong
-    else:
-        STORAGE_BACKEND_ENTRY_POINT = 'core.psql_dos'
-except MissingConfigurationError:
-    # TODO: This is actually not true anymore!
-    # Case when ``pytest`` is invoked without existing config, in which case it will rely on the automatic test profile
-    # creation which currently always uses ``core.psql_dos`` for the storage backend
-    STORAGE_BACKEND_ENTRY_POINT = 'core.psql_dos'
+except MissingConfigurationError as e:
+    raise ValueError(f"Could not parse configuration of AiiDA test profile '{test_profile}'") from e
 
-if STORAGE_BACKEND_ENTRY_POINT != 'core.psql_dos':
+if STORAGE_BACKEND_ENTRY_POINT is not None and STORAGE_BACKEND_ENTRY_POINT != 'core.psql_dos':
     collect_ignore_glob = ['*']
diff --git a/tests/storage/psql_dos/migrations/django_branch/test_migrate_to_head.py b/tests/storage/psql_dos/migrations/django_branch/test_migrate_to_head.py
index 69c7e643d9..11f9fb8c3a 100644
--- a/tests/storage/psql_dos/migrations/django_branch/test_migrate_to_head.py
+++ b/tests/storage/psql_dos/migrations/django_branch/test_migrate_to_head.py
@@ -11,6 +11,15 @@
 from aiida.storage.psql_dos.migrator import PsqlDosMigrator
 
 
+def test_all_tests_marked_as_nightly(request):
+    """Test that all tests in this folder are tagged with 'nightly' marker"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 2
+    assert 'nightly' in own_markers
+    assert 'requires_psql' in own_markers
+
+
 def test_migrate(perform_migrations: PsqlDosMigrator):
     """Test that the migrator can migrate from the base of the django branch, to the main head."""
     perform_migrations.migrate_up('django@django_0001')  # the base of the django branch
diff --git a/tests/storage/psql_dos/test_backend.py b/tests/storage/psql_dos/test_backend.py
index 6fe35ac747..bbc77b1a14 100644
--- a/tests/storage/psql_dos/test_backend.py
+++ b/tests/storage/psql_dos/test_backend.py
@@ -13,6 +13,14 @@
 from aiida.orm import User
 
 
+def test_all_tests_marked_with_requires_psql(request):
+    """Test that all tests in this folder are marked with 'requires_psql'"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 1
+    assert own_markers[0] == 'requires_psql'
+
+
 @pytest.mark.usefixtures('aiida_profile_clean')
 def test_default_user():
     assert isinstance(get_manager().get_profile_storage().default_user, User)
diff --git a/tests/test_markers.py b/tests/test_markers.py
new file mode 100644
index 0000000000..d9d6e63871
--- /dev/null
+++ b/tests/test_markers.py
@@ -0,0 +1,64 @@
+"""Tests markers that have custom in conftest.py"""
+
+import pytest
+
+
+def test_presto_auto_mark(request):
+    """Test that the presto marker is added automatically"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+    assert len(own_markers) == 1
+    assert own_markers[0] == 'presto'
+
+
+@pytest.mark.sphinx
+def test_presto_mark_and_another_mark(request):
+    """Test that presto marker is added even if there is an existing marker (except requires_rmq|psql)"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 2
+    assert 'presto' in own_markers
+    assert 'sphinx' in own_markers
+
+
+@pytest.mark.requires_rmq
+def test_no_presto_mark_if_rmq(request):
+    """Test that presto marker is NOT added if the test is mark with "requires_rmq"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 1
+    assert own_markers[0] == 'requires_rmq'
+
+
+@pytest.mark.requires_psql
+def test_no_presto_mark_if_psql(request):
+    """Test that presto marker is NOT added if the test is mark with "requires_psql"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 1
+    assert own_markers[0] == 'requires_psql'
+
+
+@pytest.mark.nightly
+def test_no_presto_mark_if_nightly(request):
+    """Test that presto marker is NOT added if the test is mark with "requires_psql"""
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 1
+    assert own_markers[0] == 'nightly'
+
+
+@pytest.mark.requires_psql
+def test_requires_psql_with_sqlite_impossible(pytestconfig):
+    db_backend = pytestconfig.getoption('--db-backend')
+    if db_backend.value == 'sqlite':
+        pytest.fail('This test should not have been executed with SQLite backend!')
+
+
+def test_daemon_client_fixture_automarked(request, daemon_client):
+    """Test that any test using ``daemon_client`` fixture is
+    automatically tagged with 'requires_rmq' mark
+    """
+    own_markers = [marker.name for marker in request.node.own_markers]
+
+    assert len(own_markers) == 1
+    assert own_markers[0] == 'requires_rmq'