Add a flag to disable caching (#92)

This PR adds a flag that can disable caching

src/pystow/cache.py

@@ -50,15 +50,19 @@ class Cached(Generic[X], ABC):
     def __init__(
         self,
         path: str | Path,
+        *,
         force: bool = False,
+        cache: bool = True,
     ) -> None:
         """Instantiate the decorator.
 
         :param path: The path to the cache for the file
+        :param cache: Should caching be done? Defaults to true, turn off for debugging purposes
         :param force: Should a pre-existing file be disregared/overwritten?
         """
         self.path = Path(path)
         self.force = force
+        self.cache = cache
 
     def __call__(self, func: Getter[X]) -> Getter[X]:
         """Apply this instance as a decorator.
@@ -69,6 +73,9 @@ def __call__(self, func: Getter[X]) -> Getter[X]:
 
         @functools.wraps(func)
         def _wrapped() -> X:
+            if not self.cache:
+                return func()
+
             if self.path.is_file() and not self.force:
                 return self.load()
             logger.debug("no cache found at %s", self.path)
@@ -158,6 +165,7 @@ class CachedDataFrame(Cached["pd.DataFrame"]):
     def __init__(
         self,
         path: str | Path,
+        cache: bool = True,
         force: bool = False,
         sep: str | None = None,
         dtype: Any | None = None,
@@ -172,7 +180,7 @@ def __init__(
         :param read_csv_kwargs: Additional kwargs to pass to :func:`pd.read_csv`.
         :raises ValueError: if sep is given as a kwarg and also in ``read_csv_kwargs``.
         """
-        super().__init__(path=path, force=force)
+        super().__init__(path=path, cache=cache, force=force)
         self.read_csv_kwargs = read_csv_kwargs or {}
         if "sep" not in self.read_csv_kwargs:
             self.sep = sep or "\t"

tests/test_caching.py

@@ -92,3 +92,24 @@ def _f2():
 
         self.assertEqual(EXPECTED_2, _f2())  # overwrites the file
         self.assertEqual(EXPECTED_2, _f1())
+
+    def test_no_cache(self) -> None:
+        """Test that no caching happens."""
+        path = self.directory.joinpath("test.pkl")
+        sentinel_value = 5
+
+        self.assertFalse(path.is_file())
+
+        @CachedPickle(path=path, cache=False)
+        def _f1() -> int:
+            return sentinel_value
+
+        self.assertFalse(path.is_file(), msg="function has not been called")
+
+        # check the following twice, just for good measure!
+        for _ in range(2):
+            self.assertEqual(sentinel_value, _f1())
+            self.assertFalse(
+                path.is_file(),
+                msg="file should not have been created since caching was turned off",
+            )