[Test] add ut for qwen3_moe.py (vllm-project#2055)

### What this PR does / why we need it?
Add ut for qwen3_moe.py

### Does this PR introduce _any_ user-facing change?
No.


- vLLM version: v0.10.0
- vLLM main:
vllm-project/vllm@18cc33d

Signed-off-by: huangxialu <[email protected]>

Author: loukong33

tests/ut/models/test_qwen3_moe.py

@@ -0,0 +1,46 @@
+#
+# 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.
+# This file is a part of the vllm-ascend project.
+#
+
+import pytest
+from vllm.model_executor.models.qwen3_moe import Qwen3MoeForCausalLM
+
+from vllm_ascend.models.qwen3_moe import CustomQwen3MoeForCausalLM
+
+
+class TestCustomQwen3MoeForCausalLM:
+
+    def test_class_inheritance(self):
+        assert issubclass(CustomQwen3MoeForCausalLM, Qwen3MoeForCausalLM)
+
+    @pytest.mark.parametrize("key, expected", [
+        ("qkv_proj", ["q_proj", "k_proj", "v_proj"]),
+        ("gate_up_proj", ["gate_proj", "up_proj"]),
+        ("experts",
+         ["experts.0.gate_proj", "experts.0.up_proj", "experts.0.down_proj"]),
+    ])
+    def test_packed_modules_mapping(self, key, expected):
+        assert CustomQwen3MoeForCausalLM.packed_modules_mapping[
+            key] == expected
+
+    def test_packed_modules_mapping_structure(self):
+        expected_mapping = {
+            "qkv_proj": ["q_proj", "k_proj", "v_proj"],
+            "gate_up_proj": ["gate_proj", "up_proj"],
+            "experts": [
+                "experts.0.gate_proj", "experts.0.up_proj",
+                "experts.0.down_proj"
+            ]
+        }
+        assert CustomQwen3MoeForCausalLM.packed_modules_mapping == expected_mapping