Fixed dropped coverage

Author: forman

zappend/context.py

@@ -50,22 +50,10 @@ def __init__(self, config: Dict[str, Any]):
         temp_storage_options = config.get("temp_storage_options")
         self._temp_dir = FileObj(temp_dir_uri, storage_options=temp_storage_options)
 
-        from .slice.factory import import_slice_source
+        from .slice.factory import to_slice_source_type
 
         slice_source = config.get("slice_source")
-        if slice_source is not None:
-            if isinstance(slice_source, str):
-                self._slice_source = import_slice_source(slice_source)
-            elif callable(slice_source):
-                self._slice_source = slice_source
-            else:
-                raise TypeError(
-                    "slice_source must a callable"
-                    " or the fully qualified name of a callable"
-                )
-
-        else:
-            self._slice_source = None
+        self._slice_source = to_slice_source_type(slice_source)
 
     def get_dataset_metadata(self, dataset: xr.Dataset) -> DatasetMetadata:
         """Get the dataset metadata from configuration and the given dataset.

zappend/slice/__init__.py

@@ -8,3 +8,4 @@
 from .factory import get_slice_dataset
 from .factory import to_slice_factories
 from .factory import to_slice_factory
+from .factory import to_slice_source_type

zappend/slice/factory.py

@@ -228,11 +228,16 @@ def normalize_slice_arg(arg: Any) -> tuple[tuple[...], dict[str, Any]]:
     return args, kwargs
 
 
-def import_slice_source(name: str) -> Callable[..., SliceObj]:
-    slice_factory = import_attribute(name)
-    if callable(slice_factory):
-        return slice_factory
-    raise TypeError(f"slice factory {name!r} must be a callable")
+def to_slice_source_type(slice_source_type: str | Type) -> Callable | None:
+    if not slice_source_type:
+        return None
+    if isinstance(slice_source_type, str):
+        slice_source_type = import_attribute(slice_source_type)
+    if not callable(slice_source_type):
+        raise TypeError(
+            "slice_source must a callable or the fully qualified name of a callable"
+        )
+    return slice_source_type
 
 
 def import_attribute(name: str) -> Any: