diff --git a/modoboa/lib/tests/__init__.py b/modoboa/lib/tests/__init__.py
index e1b5c3efb..c294c99b9 100644
--- a/modoboa/lib/tests/__init__.py
+++ b/modoboa/lib/tests/__init__.py
@@ -189,11 +189,7 @@ class ParametersMixin:
 class SimpleModoTestCase(ParametersMixin, TestCase):
     """Simple class to add parameters editing."""
 
-    @classmethod
-    def setUpTestData(cls):  # noqa
-        """Create a default user."""
-        super().setUpTestData()
-        management.call_command("load_initial_data", "--no-frontend")
+    pass
 
 
 class ModoTestCase(ParametersMixin, TestCase):
diff --git a/modoboa/maillog/tests/test_views.py b/modoboa/maillog/tests/test_views.py
index bdae83b2d..376bb97bd 100644
--- a/modoboa/maillog/tests/test_views.py
+++ b/modoboa/maillog/tests/test_views.py
@@ -53,6 +53,7 @@ class ManagementCommandsTestCase(RunCommandsMixin, SimpleModoTestCase):
     @classmethod
     def setUpTestData(cls):  # noqa
         super().setUpTestData()
+        call_command("load_initial_data", "--no-frontend")
         admin_factories.populate_database()
 
     def test_logparser(self):
diff --git a/modoboa/pdfcredentials/api/v2/tests.py b/modoboa/pdfcredentials/api/v2/tests.py
index 37c3d312a..97055452b 100644
--- a/modoboa/pdfcredentials/api/v2/tests.py
+++ b/modoboa/pdfcredentials/api/v2/tests.py
@@ -165,7 +165,7 @@ class PDFCredentialViewTestCase(ModoAPITestCase):
 
     def test_storage_dir_creation(self):
         """Test storage directory creation."""
-        self.set_global_parameter("storage_dir", "/nonexistentdir")
+        self.set_global_parameter("storage_dir", "/nonexistentdir2")
         self._create_account("leon@test.com", expected_status=500)
 
     def test_directory_check_settings(self):
diff --git a/modoboa/pdfcredentials/lib.py b/modoboa/pdfcredentials/lib.py
index 5dbd934b7..4cb165f0a 100644
--- a/modoboa/pdfcredentials/lib.py
+++ b/modoboa/pdfcredentials/lib.py
@@ -21,17 +21,18 @@ from modoboa.parameters import tools as param_tools
 def init_storage_dir():
     """Create the directory where documents will be stored."""
     storage_dir = param_tools.get_global_parameter("storage_dir")
-    if os.path.exists(storage_dir) and os.access(storage_dir, os.W_OK):
-        return
-    elif not os.access(storage_dir, os.W_OK) and os.path.exists(storage_dir):
-        raise InternalError(
-            _("Can't write to selected directory to store PDF " "documents")
-        )
+    if os.path.exists(storage_dir):
+        if os.access(storage_dir, os.W_OK):
+            return
+        else:
+            raise InternalError(
+                _("Can't write to selected directory to store PDF documents")
+            )
     try:
         os.mkdir(storage_dir)
     except OSError as inst:
         raise InternalError(
-            _("Failed to create the directory that will contain " "PDF documents (%s)")
+            _("Failed to create the directory that will contain PDF documents (%s)")
             % inst
         ) from None