[v1] add init plugin (#9716)

tests_v1/plugins/model_plugins/test_init_plugin.py

@@ -0,0 +1,56 @@
+# Copyright 2025 the LlamaFactory team.
+#
+# 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 pytest
+
+from llamafactory.v1.accelerator.interface import DistributedInterface
+from llamafactory.v1.config.arg_parser import get_args
+from llamafactory.v1.core.model_loader import ModelLoader
+
+
+def test_init_on_meta():
+    _, model_args, *_ = get_args(
+        dict(
+            model="llamafactory/tiny-random-qwen2.5",
+            init_config={"name": "init_on_meta"},
+        )
+    )
+    model_loader = ModelLoader(model_args=model_args)
+    assert model_loader.model.device.type == "meta"
+
+
+@pytest.mark.runs_on(["cuda", "npu"])
+def test_init_on_rank0():
+    _, model_args, *_ = get_args(
+        dict(
+            model="llamafactory/tiny-random-qwen2.5",
+            init_config={"name": "init_on_rank0"},
+        )
+    )
+    model_loader = ModelLoader(model_args=model_args)
+    if DistributedInterface().get_rank() == 0:
+        assert model_loader.model.device.type == "cpu"
+    else:
+        assert model_loader.model.device.type == "meta"
+
+
+def test_init_on_default():
+    _, model_args, *_ = get_args(
+        dict(
+            model="llamafactory/tiny-random-qwen2.5",
+            init_config={"name": "init_on_default"},
+        )
+    )
+    model_loader = ModelLoader(model_args=model_args)
+    assert model_loader.model.device.type == DistributedInterface().current_accelerator.type