diff --git a/radicale/tests/test_base.py b/radicale/tests/test_base.py
index 8312c25..05d45e7 100644
--- a/radicale/tests/test_base.py
+++ b/radicale/tests/test_base.py
@@ -735,6 +735,10 @@ class TestMultiFileSystem(BaseFileSystemTest, BaseRequestsMixIn):
     storage_type = "multifilesystem"
 
 
-class TestCustomStorageSystem(BaseFileSystemTest, BaseRequestsMixIn):
-    """Test BaseRequests on custom backend."""
-    storage_type = "tests.custom.storage"
\ No newline at end of file
+class TestCustomStorageSystem(BaseFileSystemTest):
+    """Test custom backend loading."""
+    storage_type = "tests.custom.storage"
+
+    def test_root(self):
+        """A simple test to verify that the custom backend works."""
+        BaseRequestsMixIn.test_root(self)