GitLab

Summary:
Pull Request resolved: https://github.com/facebookresearch/d2go/pull/192

Nowadays lightning will initialize process group when using ddp strategy, since `TestLightningTrainNet` does a training with ddp strategy (https://fburl.com/code/a9yp0kzy), the process group ended up initialized after running the test. However there're other tests that will also set up ddp and thus expect non-initialized process group, this is not a problem on sandcastle since the tests run separately, however in OSS env, the tests are running together, so the error happens (eg. https://github.com/facebookresearch/d2go/runs/5668912203?check_suite_focus=true).

This diff adds a clean up step in `TestLightningTrainNet`.

Reviewed By: tglik

Differential Revision: D35099944

fbshipit-source-id: f5b42b2a87d4efd9aa0ed97e6bd2140d80ab9522