Stop printing coverage report by default in make test / test-convergence and fix tolerance in polynorm (#1310)

## Summary

`pytest-cov` was forced on for every pytest invocation via `addopts` in
`pyproject.toml`, dumping a full per-file coverage table (~190 lines) to
the terminal on every `make test` and `make test-convergence` run (and
any ad-hoc `pytest` invocation), regardless of whether coverage was
wanted. This bloated CI/local logs significantly.

- Remove `--cov*` flags from `[tool.pytest.ini_options] addopts` in
`pyproject.toml` so coverage is no longer collected/printed by default.
- Remove the redundant `--cov` flags from the Makefile `test` target.
- Add a new opt-in `test-verbose` Makefile target (renamed from an
earlier `test-cov`) that runs the same correctness tests with both
coverage reporting (`term-missing` + `html`) and a full `--durations=0`
test-duration breakdown, for anyone who explicitly wants that diagnostic
output.
- Remove `--durations=0` from `[tool.pytest.ini_options] addopts` — this
was forcing every test's duration (slowest-first) to print on every run,
adding a large, mostly-noisy timing block to every `make test`/`make
test-convergence` run. Anyone who wants timing info can still pass
`--durations=N` (or `--durations=0` for all) manually.

### Follow-up: tightened `poly_norm` bf16 gradient tolerance

Also includes a small follow-up from review on #1309: the bf16 `atol`
used for `test_poly_norm.py::test_correctness`'s
`weight.grad`/`bias.grad` checks was loosened to `1.0`, which was
flagged as unnecessarily risky. The largest mismatch actually observed
(catastrophic cancellation in a large `sum()` reduction over up to ~524k
near-canceling terms, differing reduction order between Triton and
PyTorch — see #1309 for full root cause) was `2.25` at a value of
`~34.5`. `atol=0.5` (tolerance `2.225`) fails just under that;
`atol=0.6` (tolerance `2.325`) gives a small, deliberate margin and
passed 5/5 repeated local runs. Tightened from `1.0 → 0.6`.

## Testing Done

1. Verified plain `pytest` / `make test` / `make test-convergence` no
longer print coverage tables.
2. Verified `make test-cov` (opt-in) still produces the full coverage
report as before.
3. Ran `test_poly_norm.py::test_correctness[dtype1-...]` (bf16) 5x with
`atol=0.6` — all passed. Ran the full `test_poly_norm.py` +
`test_fused_add_rms_norm.py` suites 3x — consistently `55 passed, 2
xfailed`.


- Hardware Type: H100
- [x] run `make test` to ensure correctness
- [x] run `make checkstyle` to ensure code style
- [ ] run `make test-convergence` to ensure convergence

---------

Co-authored-by: Copilot <[email protected]>

Makefile

@@ -1,13 +1,22 @@
-.PHONY: test checkstyle test-convergence all serve build clean
+.PHONY: test test-verbose checkstyle test-convergence all serve build clean
 
 
 all: checkstyle test test-convergence
 
 # Command to run pytest for correctness tests
 test:
+	python -m pytest --disable-warnings \
+		--ignore=test/convergence \
+		test/
+
+# Command to run pytest for correctness tests with coverage reporting and full test-duration breakdown
+test-verbose:
 	python -m pytest --disable-warnings \
 		--cov=src/liger_kernel \
 		--cov-report=term-missing \
+		--cov-report=html \
+		--cov-config=pyproject.toml \
+		--durations=0 \
 		--ignore=test/convergence \
 		test/
 

pyproject.toml

@@ -24,13 +24,6 @@ pythonpath = ["src", "."]
 asyncio_mode = "auto"
 log_cli = true
 log_cli_level = "INFO"
-addopts = [
-    "--cov=src/liger_kernel",
-    "--cov-report=term-missing",
-    "--cov-report=html",
-    "--cov-config=pyproject.toml",
-    "--durations=0"
-]
 python_files = "test_*.py"
 testpaths = ["test/"]
 

test/transformers/test_poly_norm.py

@@ -99,7 +99,7 @@ class NaivePolyNorm(nn.Module):
         (torch.float32, 3e-4, 1e-6),
         pytest.param(
             torch.bfloat16,
-            1.0,
+            6e-1,
             5e-2,
             marks=pytest.mark.skipif(not supports_bfloat16(), reason="bfloat16 not supported on this GPU"),
         ),