Fix unclosed file warnings in json.load() calls

The json.load(open(...)) pattern leaves file handles open, causing
ResourceWarning when Python is run with warnings enabled. This is
particularly noisy when using multiprocessing, as each worker triggers
the warning when importing the module.

Changes:
- neuropixels_tools.py: Use context manager in _load_np_probe_features()
- testing.py: Use context manager when loading JSON schema

Both files now properly close file handles using 'with' statements.

Fixes issue reported for Python 3.14 on Linux with forkserver multiprocessing.

Author: grahamfindlay

src/probeinterface/neuropixels_tools.py

@@ -28,7 +28,8 @@ def _load_np_probe_features():
     global _np_probe_features
     if _np_probe_features is None:
         probe_features_filepath = Path(__file__).absolute().parent / Path("resources/neuropixels_probe_features.json")
-        _np_probe_features = json.load(open(probe_features_filepath, "r"))
+        with open(probe_features_filepath, "r") as f:
+            _np_probe_features = json.load(f)
     return _np_probe_features
 
 

src/probeinterface/testing.py

@@ -4,7 +4,8 @@
 from probeinterface import __version__ as version
 
 json_schema_file = Path(__file__).absolute().parent / "schema" / "probe.json.schema"
-schema = json.load(open(json_schema_file, "r"))
+with open(json_schema_file, "r") as f:
+    schema = json.load(f)
 
 
 def validate_probe_dict(probe_dict):