fix: create storage directories in test fixtures for StorageBackend validation

All 24 object storage test failures were due to test fixtures not creating
the directories they configured. StorageBackend validates that file protocol
locations exist, so fixtures must create them.

- conftest.py: Create test_project subdirectory in object_storage_config
- test_update1.py: Create djtest subdirectories in mock_stores_update

Test results: 520 passed, 7 skipped, 0 failures ✓

Author: dimitri-yatsenko

tests/conftest.py

@@ -827,6 +827,9 @@ def object_storage_config(tmpdir_factory):
     base_location = str(tmpdir_factory.mktemp("object_storage"))
     # Location now includes project context
     location = f"{base_location}/test_project"
+    # Create the directory (StorageBackend validates it exists)
+    from pathlib import Path
+    Path(location).mkdir(parents=True, exist_ok=True)
     return {
         "protocol": "file",
         "location": location,

tests/integration/test_update1.py

@@ -24,13 +24,19 @@ class Thing(dj.Manual):
 @pytest.fixture(scope="module")
 def mock_stores_update(tmpdir_factory):
     """Configure stores for update tests using unified stores system."""
+    from pathlib import Path
+
     og_stores = dict(dj.config.stores)
 
     # Configure stores (location includes project context)
     store_location = str(tmpdir_factory.mktemp("store")) + "/djtest"
     repo_stage = str(tmpdir_factory.mktemp("repo_stage"))
     repo_location = str(tmpdir_factory.mktemp("repo_loc")) + "/djtest"
 
+    # Create the directories (StorageBackend validates they exist)
+    Path(store_location).mkdir(parents=True, exist_ok=True)
+    Path(repo_location).mkdir(parents=True, exist_ok=True)
+
     dj.config.stores["update_store"] = dict(
         protocol="file",
         location=store_location,