Add XPU expected slice for SlowBnb4BitFluxControlWithLoraTests::test_lora_loading (#14202)

* fix xpu slice

Signed-off-by: jiqing-feng <jiqing.feng@intel.com>

* complete comment

Signed-off-by: jiqing-feng <jiqing.feng@intel.com>

---------

Signed-off-by: jiqing-feng <jiqing.feng@intel.com>

Author: jiqing-feng

tests/quantization/bnb/test_mixed_int8.py

@@ -34,6 +34,7 @@
 
 from ...testing_utils import (
     CaptureLogger,
+    Expectations,
     backend_empty_cache,
     is_bitsandbytes_available,
     is_torch_available,
@@ -693,7 +694,16 @@ def test_lora_loading(self):
             generator=torch.Generator().manual_seed(42),
         ).images
         out_slice = output[0, -3:, -3:, -1].flatten()
-        expected_slice = np.array([0.2029, 0.2136, 0.2268, 0.1921, 0.1997, 0.2185, 0.2021, 0.2183, 0.2292])
+        # Hardware-dependent: the Control LoRA dequantizes and expands `x_embedder`, and the error
+        # accumulates over the 8 denoising steps enough that even different CUDA GPUs disagree, so
+        # reference slices are stored per accelerator backend.
+        expected_slices = Expectations(
+            {
+                (None, None): np.array([0.2029, 0.2136, 0.2268, 0.1921, 0.1997, 0.2185, 0.2021, 0.2183, 0.2292]),
+                ("xpu", 5): np.array([0.0955, 0.1223, 0.1509, 0.0872, 0.1155, 0.1890, 0.0754, 0.1028, 0.2178]),
+            }
+        )
+        expected_slice = expected_slices.get_expectation()
 
         max_diff = numpy_cosine_similarity_distance(expected_slice, out_slice)
         assert max_diff < 1e-3, f"{out_slice=} != {expected_slice=}"