mlx - fix for ops/core_test.py (#19599)

* fix for ops/core_test.py

* revert cast int64 to  int32  removal

Author: lkarthee

keras/src/backend/mlx/core.py

@@ -230,22 +230,37 @@ def scatter_update(inputs, indices, updates):
 
 def slice(inputs, start_indices, shape):
     inputs = convert_to_tensor(inputs)
-
+    if not isinstance(shape, list):
+        shape = convert_to_tensor(shape, dtype="int32").tolist()
+    else:
+        shape = [i if isinstance(i, int) else i.item() for i in shape]
+    if not isinstance(start_indices, list):
+        start_indices = convert_to_tensor(start_indices, dtype="int32").tolist()
+    else:
+        start_indices = [
+            i if isinstance(i, int) else i.item() for i in start_indices
+        ]
     python_slice = __builtins__["slice"]
     slices = tuple(
-        python_slice(int(start_index), int(start_index + length))
+        python_slice(start_index, start_index + length)
         for start_index, length in zip(start_indices, shape)
     )
     return inputs[slices]
 
 
 def slice_update(inputs, start_indices, updates):
     inputs = convert_to_tensor(inputs)
+    if not isinstance(start_indices, list):
+        start_indices = convert_to_tensor(start_indices, dtype="int32").tolist()
+    else:
+        start_indices = [
+            i if isinstance(i, int) else i.item() for i in start_indices
+        ]
     updates = convert_to_tensor(updates)
 
     python_slice = __builtins__["slice"]
     slices = tuple(
-        python_slice(int(start_index), int(start_index + update_length))
+        python_slice(start_index, start_index + update_length)
         for start_index, update_length in zip(start_indices, updates.shape)
     )
     inputs[slices] = updates

keras/src/ops/core_test.py

@@ -468,6 +468,10 @@ def test_cast(self):
     @parameterized.named_parameters(
         ("float8_e4m3fn", "float8_e4m3fn"), ("float8_e5m2", "float8_e5m2")
     )
+    @pytest.mark.skipif(
+        backend.backend() == "mlx",
+        reason=f"{backend.backend()} doesn't support `float8`.",
+    )
     def test_cast_float8(self, float8_dtype):
         # Cast to float8 and cast back
         x = ops.ones((2,), dtype="float32")
@@ -584,6 +588,8 @@ class CoreOpsDtypeTest(testing.TestCase, parameterized.TestCase):
         ALL_DTYPES = [
             x for x in ALL_DTYPES if x not in ["uint16", "uint32", "uint64"]
         ]
+    elif backend.backend() == "mlx":
+        ALL_DTYPES = [x for x in ALL_DTYPES if x not in ["float64"]]
     # Remove float8 dtypes for the following tests
     ALL_DTYPES = [x for x in ALL_DTYPES if x not in dtypes.FLOAT8_TYPES]