diff --git a/openslides/core/apps.py b/openslides/core/apps.py
index 413ac7a67..3c56b60d9 100644
--- a/openslides/core/apps.py
+++ b/openslides/core/apps.py
@@ -6,6 +6,7 @@ from django.apps import AppConfig
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.db.models.signals import post_migrate
+from django.db.utils import OperationalError
 
 from ..utils.projector import register_projector_elements
 
@@ -43,8 +44,8 @@ class CoreAppConfig(AppConfig):
         # Set constants
         try:
             set_constants(get_constants_from_apps())
-        except ImproperlyConfigured:
-            # Database is not loaded. This happens in tests.
+        except (ImproperlyConfigured, OperationalError):
+            # Database is not loaded. This happens in tests and migrations.
             pass
 
         # Define config variables and projector elements.
diff --git a/requirements/development.txt b/requirements/development.txt
index e5119b485..b4440966f 100644
--- a/requirements/development.txt
+++ b/requirements/development.txt
@@ -4,7 +4,7 @@ coverage
 git+https://gitlab.com/pycqa/flake8.git
 isort
 mypy
-pytest>=3.7.2
+pytest>=3.6,<3.7
 pytest-django
 pytest-asyncio
 pytest-cov
diff --git a/tests/conftest.py b/tests/conftest.py
index d029d2942..d06807c9e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -9,7 +9,7 @@ def pytest_collection_modifyitems(items):
     Helper until https://github.com/pytest-dev/pytest-django/issues/214 is fixed.
     """
     def get_marker_transaction(test):
-        marker = test.get_marker('django_db')
+        marker = test.get_closest_marker('django_db')
         if marker:
             validate_django_db(marker)
             return marker.kwargs['transaction']