Fix failing tests: remove negative axis cases from CumOp tests

- Updated TestCumOp.test_grad to only test non-negative axis values when directly instantiating CumOp
- Updated Numba CumOp test to remove axis=None and axis=-1 cases that fail with new CumOp constructor
- CumOp constructor now rejects negative axis values, but helper functions handle axis normalization

Co-authored-by: ricardoV94 <[email protected]>

Author: Copilot

tests/link/numba/test_extra_ops.py

@@ -40,7 +40,7 @@ def test_Bartlett(val):
         ),
         (
             (pt.dtensor3(), np.arange(30, dtype=config.floatX).reshape((2, 3, 5))),
-            -1,
+            2,
             "add",
         ),
         (
@@ -53,11 +53,6 @@ def test_Bartlett(val):
             1,
             "add",
         ),
-        (
-            (pt.matrix(), np.arange(6, dtype=config.floatX).reshape((3, 2))),
-            None,
-            "add",
-        ),
         (
             (pt.matrix(), np.arange(6, dtype=config.floatX).reshape((3, 2))),
             0,
@@ -68,11 +63,6 @@ def test_Bartlett(val):
             1,
             "mul",
         ),
-        (
-            (pt.matrix(), np.arange(6, dtype=config.floatX).reshape((3, 2))),
-            None,
-            "mul",
-        ),
     ],
 )
 def test_CumOp(val, axis, mode):

tests/tensor/test_extra_ops.py

@@ -238,7 +238,8 @@ def test_grad(self):
         utt.verify_grad(lambda x: cumsum(x), [a])  # Test axis=None for cumsum
         utt.verify_grad(lambda x: cumprod(x), [a])  # Test axis=None for cumprod
 
-        for axis in range(-len(a.shape), len(a.shape)):
+        # Test only non-negative axis values for Op level (negative axis not allowed)
+        for axis in range(len(a.shape)):
             utt.verify_grad(self.op_class(axis=axis, mode="add"), [a], eps=4e-4)
             utt.verify_grad(self.op_class(axis=axis, mode="mul"), [a], eps=4e-4)