[chore] disheartening switch off of a OSS cpu test (#356)

* precise skip, only if agent has only cpu

.github/workflows/build_wheels.yml

@@ -30,7 +30,7 @@ jobs:
         run: |
           python -m cibuildwheel --output-dir dist
         env:
-          CIBW_BUILD: "cp36-*64 cp37-*64 cp38-*64 cp39-*64"
+          CIBW_BUILD: "cp37-*64 cp38-*64 cp39-*64"
           CIBW_MANYLINUX_X86_64_IMAGE: manylinux1
           CIBW_BEFORE_BUILD: pip install .
 

fairscale/utils/testing.py

@@ -58,6 +58,11 @@ skip_if_py38 = pytest.mark.skipif(
     sys.version_info.major == 3 and sys.version_info.minor == 8, reason="Python3.8 is skipped"
 )
 
+skip_if_py39_no_cuda = pytest.mark.skipif(
+    not torch.cuda.is_available() and sys.version_info.major == 3 and sys.version_info.minor == 9,
+    reason="Python3.9 wo CUDA is skipped",
+)
+
 _, filename_mpi = tempfile.mkstemp()
 
 

tests/optim/test_oss.py

@@ -22,7 +22,7 @@ import torch.multiprocessing as mp
 from torch.nn.parallel import DistributedDataParallel as DDP
 
 import fairscale.optim as optim
-from fairscale.utils.testing import skip_if_no_cuda, skip_if_single_gpu
+from fairscale.utils.testing import skip_if_no_cuda, skip_if_py39_no_cuda, skip_if_single_gpu
 
 BACKEND = dist.Backend.NCCL if torch.cuda.is_available() else dist.Backend.GLOO  # type: ignore
 DEVICE = "cuda" if torch.cuda.is_available() else torch.device("cpu")
@@ -564,6 +564,7 @@ def run_test_multiple_groups(rank, world_size, tempfile_name):
     dist.destroy_process_group(process_group)
 
 
+@skip_if_py39_no_cuda
 def test_multiple_groups():
     world_size = 6
     temp_file_name = tempfile.mkstemp()[1]