[POC] Base class for dataset tests (#3402)

* add base class for datasets tests

* add better type hints

* add documentation to subclasses

* add utility functions to create files / folders of random images and videos

* fix imports

* remove class properties

* fix smoke test

* fix type hints

* fix random size generation

* add Caltech256 as example

* add utility function to create grid of combinations

* add CIFAR100? as example

* lint

* add missing import

* improve documentation

* create 1 frame videos by default

* remove obsolete check

* return path of files created with utility functions

* [test] close PIL file handles before deletion

* fix video folder creation

* generalize file handle closing

* fix lazy imports

* add test for transforms

* fix explanation comment

* lint

* force load opened PIL images

* lint

* copy default config to avoid inplace modification

* enable additional arg forwarding

Author: pmeier

test/common_utils.py

@@ -393,3 +393,11 @@ def int_dtypes():
 
 def float_dtypes():
     return torch.testing.floating_types()
+
+
+@contextlib.contextmanager
+def disable_console_output():
+    with contextlib.ExitStack() as stack, open(os.devnull, "w") as devnull:
+        stack.enter_context(contextlib.redirect_stdout(devnull))
+        stack.enter_context(contextlib.redirect_stderr(devnull))
+        yield