Code review

Author: crusaderky

src/array_api_extra/_lib/_utils/_helpers.py

@@ -279,6 +279,9 @@ def capabilities(xp: ModuleType) -> dict[str, int]:
     """
     Return patched ``xp.__array_namespace_info__().capabilities()``.
 
+    TODO this helper should be eventually removed once all the special cases
+    it handles are fixed in the respective backends.
+
     Parameters
     ----------
     xp : array_namespace

tests/test_funcs.py

@@ -838,9 +838,7 @@ def test_all_equal(self, xp: ModuleType):
         xp_assert_equal(nunique(a), xp.asarray(1))
 
     @pytest.mark.xfail_xp_backend(Backend.DASK, reason="No equal_nan kwarg in unique")
-    @pytest.mark.xfail_xp_backend(
-        Backend.SPARSE, reason="Non-compliant equal_nan=True behaviour"
-    )
+    @pytest.mark.xfail_xp_backend(Backend.SPARSE, reason="sparse#855")
     def test_nan(self, xp: ModuleType, library: Backend):
         if library.like(Backend.NUMPY) and NUMPY_VERSION < (1, 24):
             pytest.xfail("NumPy <1.24 has no equal_nan kwarg in unique")