fix bugs

tests/conftest.py

@@ -1,10 +1,10 @@
 import io
-import json
 import os
 import tempfile
 from pathlib import Path
 
 import pytest
+import yaml
 from PIL import Image as PILImage
 
 from spectra.web.server import create_app
@@ -18,11 +18,16 @@ def app():
     with tempfile.TemporaryDirectory() as tmpdir:
         tmp = Path(tmpdir)
         cache_dir = tmp / "cache"
+        config_path = tmp / "config.yaml"
+
+        # Write a minimal config so ConfigManager writes into the temp dir
+        with open(config_path, "w") as f:
+            yaml.dump({"display": {"saturation": 0.5}}, f)
 
         old_environ = os.environ.get("SPECTRA_CACHE_DIR")
         os.environ["SPECTRA_CACHE_DIR"] = str(cache_dir)
 
-        app = create_app()
+        app = create_app(config_path=str(config_path))
 
         yield app