Clean up Backend tests

Author: crusaderky

src/array_api_extra/_lib/_backends.py

@@ -1,9 +1,10 @@
 """Backends with which array-api-extra interacts in delegation and testing."""
 
+from __future__ import annotations
+
 from collections.abc import Callable
 from enum import Enum
 from types import ModuleType
-from typing import cast
 
 from ._utils import _compat
 
@@ -23,10 +24,14 @@ class Backend(Enum):  # numpydoc ignore=PR01,PR02  # type: ignore[no-subclass-an
         corresponding to the backend.
     """
 
+    # Use :<tag> to prevent Enum from deduplicating items with the same value
     ARRAY_API_STRICT = "array_api_strict", _compat.is_array_api_strict_namespace
-    ARRAY_API_STRICTEST = "array_api_strictest", _compat.is_array_api_strict_namespace
+    ARRAY_API_STRICTEST = (
+        "array_api_strict:strictest",
+        _compat.is_array_api_strict_namespace,
+    )
     NUMPY = "numpy", _compat.is_numpy_namespace
-    NUMPY_READONLY = "numpy_readonly", _compat.is_numpy_namespace
+    NUMPY_READONLY = "numpy:readonly", _compat.is_numpy_namespace
     CUPY = "cupy", _compat.is_cupy_namespace
     TORCH = "torch", _compat.is_torch_namespace
     DASK = "dask.array", _compat.is_dask_namespace
@@ -49,4 +54,13 @@ def __init__(
 
     def __str__(self) -> str:  # type: ignore[explicit-override]  # pyright: ignore[reportImplicitOverride]  # numpydoc ignore=RT01
         """Pretty-print parameterized test names."""
-        return cast(str, self.value)
+        return self.name.lower()
+
+    @property
+    def modname(self) -> str:  # numpydoc ignore=RT01
+        """Module name to be imported."""
+        return self.value.split(":")[0]
+
+    def like(self, *others: Backend) -> bool:  # numpydoc ignore=PR01,RT01
+        """Check if this backend uses the same module as others."""
+        return any(self.modname == other.modname for other in others)

tests/conftest.py

@@ -19,6 +19,7 @@
 T = TypeVar("T")
 P = ParamSpec("P")
 
+NUMPY_VERSION = tuple(int(v) for v in np.__version__.split(".")[2])
 np_compat = array_namespace(np.empty(0))  # type: ignore[arg-type]  # pyright: ignore[reportArgumentType]
 
 
@@ -43,7 +44,7 @@ def library(request: pytest.FixtureRequest) -> Backend:  # numpydoc ignore=PR01,
                 msg = f"argument of {marker_name} must be a Backend enum"
                 raise TypeError(msg)
             if library == elem:
-                reason = library.value
+                reason = str(library)
                 with suppress(KeyError):
                     reason += ":" + cast(str, marker.kwargs["reason"])
                 skip_or_xfail(reason=reason)
@@ -116,14 +117,14 @@ def xp(
         yield NumPyReadOnly()  # type: ignore[misc]  # pyright: ignore[reportReturnType]
         return
 
-    if (
-        library in (Backend.ARRAY_API_STRICT, Backend.ARRAY_API_STRICTEST)
-        and np.__version__ < "1.26"
-    ):
+    if library.like(Backend.ARRAY_API_STRICT) and NUMPY_VERSION < (1, 26):
         pytest.skip("array_api_strict is untested on NumPy <1.26")
 
+    xp = pytest.importorskip(library.modname)
+    # Possibly wrap module with array_api_compat
+    xp = array_namespace(xp.empty(0))
+
     if library == Backend.ARRAY_API_STRICTEST:
-        xp = pytest.importorskip("array_api_strict")
         with xp.ArrayAPIStrictFlags(
             boolean_indexing=False,
             data_dependent_shapes=False,
@@ -134,10 +135,6 @@ def xp(
             yield xp
         return
 
-    xp = pytest.importorskip(library.value)
-    # Possibly wrap module with array_api_compat
-    xp = array_namespace(xp.empty(0))
-
     # On Dask and JAX, monkey-patch all functions tagged by `lazy_xp_function`
     # in the global scope of the module containing the test function.
     patch_lazy_xp_functions(request, monkeypatch, xp=xp)
@@ -147,8 +144,6 @@ def xp(
 
         # suppress unused-ignore to run mypy in -e lint as well as -e dev
         jax.config.update("jax_enable_x64", True)  # type: ignore[no-untyped-call,unused-ignore]
-        yield xp
-        return
 
     yield xp
 

tests/test_at.py

@@ -257,10 +257,7 @@ def test_incompatible_dtype(
     elif library is Backend.DASK:
         z = at_op(x, idx, op, 1.1, copy=copy)
 
-    elif (
-        library in (Backend.ARRAY_API_STRICT, Backend.ARRAY_API_STRICTEST)
-        and op is not _AtOp.SET
-    ):
+    elif library.like(Backend.ARRAY_API_STRICT) and op is not _AtOp.SET:
         with pytest.raises(Exception, match=r"cast|promote|dtype"):
             _ = at_op(x, idx, op, 1.1, copy=copy)
 

tests/test_funcs.py

@@ -32,6 +32,8 @@
 from array_api_extra._lib._utils._typing import Array, Device
 from array_api_extra.testing import lazy_xp_function
 
+from .conftest import NUMPY_VERSION
+
 # some xp backends are untyped
 # mypy: disable-error-code=no-untyped-def
 
@@ -48,9 +50,6 @@
 lazy_xp_function(sinc, static_argnames="xp")
 
 
-NUMPY_VERSION = tuple(int(v) for v in np.__version__.split(".")[2])
-
-
 class TestApplyWhere:
     @staticmethod
     def f1(x: Array, y: Array | int = 10) -> Array:
@@ -197,7 +196,7 @@ def test_device(self, xp: ModuleType, device: Device):
         y = apply_where(x % 2 == 0, x, self.f1, fill_value=x)
         assert get_device(y) == device
 
-    @pytest.mark.xfail_xp_backend(Backend.SPARSE, reason="no isdtype")
+    @pytest.mark.skip_xp_backend(Backend.SPARSE, reason="no isdtype")
     @pytest.mark.filterwarnings("ignore::RuntimeWarning")  # overflows, etc.
     @hypothesis.settings(
         # The xp and library fixtures are not regenerated between hypothesis iterations
@@ -223,7 +222,7 @@ def test_hypothesis(  # type: ignore[explicit-any,decorated-any]
         library: Backend,
     ):
         if (
-            library in (Backend.NUMPY, Backend.NUMPY_READONLY)
+            library.like(Backend.NUMPY)
             and NUMPY_VERSION < (2, 0)
             and dtype is np.float32
         ):
@@ -843,8 +842,7 @@ def test_all_equal(self, xp: ModuleType):
         Backend.SPARSE, reason="Non-compliant equal_nan=True behaviour"
     )
     def test_nan(self, xp: ModuleType, library: Backend):
-        is_numpy = library in (Backend.NUMPY, Backend.NUMPY_READONLY)
-        if is_numpy and NUMPY_VERSION < (1, 24):
+        if library.like(Backend.NUMPY) and NUMPY_VERSION < (1, 24):
             pytest.xfail("NumPy <1.24 has no equal_nan kwarg in unique")
 
         # Each NaN is counted separately

tests/test_testing.py

@@ -223,7 +223,7 @@ def test_lazy_xp_function_cython_ufuncs(xp: ModuleType, library: Backend):
     pytest.importorskip("scipy")
     assert erf is not None
     x = xp.asarray([6.0, 7.0])
-    if library in (Backend.ARRAY_API_STRICT, Backend.ARRAY_API_STRICTEST, Backend.JAX):
+    if library.like(Backend.ARRAY_API_STRICT, Backend.JAX):
         # array-api-strict arrays are auto-converted to NumPy
         # which results in an assertion error for mismatched namespaces
         # eager JAX arrays are auto-converted to NumPy in eager JAX