test fixes

Summary: Some random seed changes. Skip multigpu tests when there's only one gpu. This is a better fix for what AI is doing in D80600882.

Reviewed By: MichaelRamamonjisoa

Differential Revision: D80625966

fbshipit-source-id: ac3952e7144125fd3a05ad6e4e6e5976ae10a8ef

tests/common_testing.py

@@ -31,6 +31,13 @@ def skip_opengl_requested() -> bool:
 usesOpengl = unittest.skipIf(skip_opengl_requested(), "uses opengl")
 
 
+def have_multiple_gpus() -> bool:
+    return torch.cuda.device_count() > 1
+
+
+needs_multigpu = unittest.skipIf(not have_multiple_gpus(), "needs multiple GPUs")
+
+
 def get_tests_dir() -> Path:
     """
     Returns Path for the directory containing this file.