Xfail sparse test on numba

Author: ricardoV94

tests/test_splines.py

@@ -17,13 +17,29 @@
 import pytensor.tensor as pt
 import pytest
 
+from numba import TypingError
+from pytensor.compile import get_default_mode
+from pytensor.link.numba import NumbaLinker
 from pytensor.sparse import SparseTensorType
 
 import pymc_extras as pmx
 
 
 @pytest.mark.parametrize("dtype", [np.float32, np.float64])
-@pytest.mark.parametrize("sparse", [True, False])
+@pytest.mark.parametrize(
+    "sparse",
+    [
+        pytest.param(
+            True,
+            marks=pytest.mark.xfail(
+                condition=isinstance(get_default_mode().linker, NumbaLinker),
+                reason="numba backend does not yet support sparse variables",
+                raises=TypingError,
+            ),
+        ),
+        False,
+    ],
+)
 def test_spline_construction(dtype, sparse):
     x = np.linspace(0, 1, 20, dtype=dtype)
     np_out = pmx.utils.spline.numpy_bspline_basis(x, 10, 3)