gh-915: Fail tests if array backend not found (#917)

Co-authored-by: Patrick J. Roddy <patrickjamesroddy@gmail.com>

Author: connoraird

tests/fixtures/array_backends.py

@@ -7,7 +7,6 @@
 
 from __future__ import annotations
 
-import contextlib
 import importlib.metadata
 import os
 from typing import TYPE_CHECKING
@@ -89,14 +88,9 @@ def _import_and_add_jax(xp_available_backends: dict[str, ModuleType]) -> None:
     _import_and_add_jax(xp_available_backends)
 # if all, try importing every backend
 elif ARRAY_BACKEND == "all":
-    with contextlib.suppress(ImportError):
-        _import_and_add_numpy(xp_available_backends)
-
-    with contextlib.suppress(ImportError):
-        _import_and_add_array_api_strict(xp_available_backends)
-
-    with contextlib.suppress(ImportError):
-        _import_and_add_jax(xp_available_backends)
+    _import_and_add_numpy(xp_available_backends)
+    _import_and_add_array_api_strict(xp_available_backends)
+    _import_and_add_jax(xp_available_backends)
 else:
     msg = f"unsupported array backend: {ARRAY_BACKEND}"
     raise ValueError(msg)