Add a decorator for marking slow tests. (#18231)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18231
ghimport-source-id: 78c230f60c41877fe91b89c8c979b160f36f856b
Stack from [ghstack](https://github.com/ezyang/ghstack):
* **#18231 Add a decorator for marking slow tests.**
The general strategy:
- It's a normal skip decorator, which triggers a skip if
PYTORCH_TEST_WITH_SLOW is not set.
- It also annotates the method in question that says it's
slow. We use this to implement a catch-all skipper in
setUp that skips all non-slow tests when
PYTORCH_TEST_SKIP_FAST is set.
I added a little smoketest to test_torch and showed that I get:
```
Ran 432 tests in 0.017s
OK (skipped=431)
```
when running with PYTORCH_TEST_WITH_SLOW=1 and PYTORCH_TEST_SKIP_FAST=1
CI integration coming in later patch, as well as nontrivial uses of
this decorator.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Differential Revision: D14544441
fbshipit-source-id: 54435ce4ec827193e019887178c09ebeae3ae2c9
