| name | run-cpu-tests |
| description | How to write and run verl-omni CPU tests (test_*_on_cpu.py) that exercise adapters, rewards, and configs without a GPU or model weights. Use when adding tests, reproducing a failure locally, or producing the test evidence a PR body requires. |
Run & Write CPU Tests
docs/contributing/testing_guide.md is authoritative for the layer hierarchy, the
*_on_cpu.py naming rule, placement, coverage, the local pytest invocations, and
the steps for adding a test. Follow it. This skill adds what it does not cover.
What CI does that the guide's local commands don't
- The CPU job exports
TORCH_COMPILE_DISABLE=1 and TORCHINDUCTOR_DISABLE=1
(.github/workflows/cpu_unit_tests.yml). Set both locally when reproducing a
failure that only CI sees.
- On pull requests the job triggers on
types: [labeled] and only when the label
is ci — a green checks page on an unlabelled PR means the tests never ran. The
label is single-use: drop-ci-labels.yml removes it on every synchronize, so a
new push does not re-run the job until you re-add ci.
tests/special_sanity/ runs as its own job; those files are test_*.py, so the
CPU job's python_files override deliberately skips them.
Idioms the guide leaves to the reader
Configs — construct normally:
cfg = DiffusionLossConfig(loss_mode="flow_dppo")
Bypass __init__ only when __post_init__ does I/O (loading tokenizers, resolving
paths), as DiffusionModelConfig does:
cfg = object.__new__(DiffusionModelConfig)
object.__setattr__(cfg, "architecture", "QwenImagePipeline")
object.__setattr__(cfg, "algorithm", "dpo")
object.__setattr__ is needed because BaseConfig gates assignment through
_mutable_fields, not because the dataclass is frozen
(config.md). Reaching for this where plain construction
works is a review comment.
Mocks and assertions — MagicMock the transformer and assert on call args and
output shapes rather than on real model output. TensorDict batches usually carry
metadata, not pixels (TensorDict({}, batch_size=2) plus the fields under test).
Use torch.testing.assert_close(a, b, rtol=..., atol=...) for tensors and
pytest.approx for scalars — never .equal() on floats.
Before opening a PR
Paste the command and its output into the PR body (mandatory —
commit-and-pr), then run pre-commit run --all-files.
