From d9b73ffd5155507c7990aa792b439b886c35dbb9 Mon Sep 17 00:00:00 2001
From: DN6 <dhruv.nair@gmail.com>
Date: Mon, 15 Dec 2025 16:12:50 +0530
Subject: [PATCH] update

---
 tests/models/testing_utils/parallelism.py | 102 ++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 tests/models/testing_utils/parallelism.py

diff --git a/tests/models/testing_utils/parallelism.py b/tests/models/testing_utils/parallelism.py
new file mode 100644
index 0000000000..3bbbfe91bb
--- /dev/null
+++ b/tests/models/testing_utils/parallelism.py
@@ -0,0 +1,102 @@
+# coding=utf-8
+# Copyright 2025 HuggingFace Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+import pytest
+import torch
+import torch.multiprocessing as mp
+
+from diffusers.models._modeling_parallel import ContextParallelConfig
+
+from ...testing_utils import (
+    is_context_parallel,
+    require_torch_multi_accelerator,
+)
+
+
+def _context_parallel_worker(rank, world_size, model_class, init_dict, cp_dict, inputs_dict, result_queue):
+    try:
+        # Setup distributed environment
+        os.environ["MASTER_ADDR"] = "localhost"
+        os.environ["MASTER_PORT"] = "12355"
+
+        torch.distributed.init_process_group(
+            backend="nccl",
+            init_method="env://",
+            world_size=world_size,
+            rank=rank,
+        )
+        torch.cuda.set_device(rank)
+        device = torch.device(f"cuda:{rank}")
+
+        model = model_class(**init_dict)
+        model.to(device)
+        model.eval()
+
+        inputs_on_device = {}
+        for key, value in inputs_dict.items():
+            if isinstance(value, torch.Tensor):
+                inputs_on_device[key] = value.to(device)
+            else:
+                inputs_on_device[key] = value
+
+        cp_config = ContextParallelConfig(**cp_dict)
+        model.enable_parallelism(config=cp_config)
+
+        with torch.no_grad():
+            output = model(**inputs_on_device, return_dict=False)[0]
+
+        if rank == 0:
+            result_queue.put(("success", output.shape))
+
+    except Exception as e:
+        if rank == 0:
+            result_queue.put(("error", str(e)))
+    finally:
+        if torch.distributed.is_initialized():
+            torch.distributed.destroy_process_group()
+
+
+@is_context_parallel
+@require_torch_multi_accelerator
+class ContextParallelTesterMixin:
+    base_precision = 1e-3
+
+    @pytest.mark.parametrize("cp_type", ["ulysses_degree", "ring_degree"], ids=["ulysses", "ring"])
+    def test_context_parallel_inference(self, cp_type):
+        if not torch.distributed.is_available():
+            pytest.skip("torch.distributed is not available.")
+
+        if not hasattr(self.model_class, "_cp_plan") or self.model_class._cp_plan is None:
+            pytest.skip("Model does not have a _cp_plan defined for context parallel inference.")
+
+        world_size = 2
+        init_dict = self.get_init_dict()
+        inputs_dict = self.get_dummy_inputs()
+        cp_dict = {cp_type: world_size}
+
+        ctx = mp.get_context("spawn")
+        result_queue = ctx.Queue()
+
+        mp.spawn(
+            _context_parallel_worker,
+            args=(world_size, self.model_class, init_dict, cp_dict, inputs_dict, result_queue),
+            nprocs=world_size,
+            join=True,
+        )
+
+        status, result = result_queue.get(timeout=60)
+        assert status == "success", f"Context parallel inference failed: {result}"