[Test] Add unit test for schedule_config.py (#1590)

What this PR does / why we need it?
According to issue
#1298 , this pull
request adds unit test code for schedule_config.py.

Does this PR introduce any user-facing change?
No

How was this patch tested?
CI passed with new added/existing test.

- vLLM version: v0.9.2
- vLLM main:
vllm-project/vllm@8d0a01a

Author: nuclearwu

tests/ut/core/test_schedule_config.py

@@ -0,0 +1,117 @@
+#
+# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
+#
+# 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.
+
+from vllm.config import SchedulerConfig
+
+from tests.ut.base import TestBase
+from vllm_ascend.core.schedule_config import AscendSchedulerConfig
+
+
+class TestAscendSchedulerConfig(TestBase):
+
+    def setUp(self):
+        self.basic_scheduler_config = SchedulerConfig(
+            max_num_batched_tokens=8192,
+            is_multimodal_model=False,
+            send_delta_data=False,
+            scheduler_delay_factor=0,
+        )
+
+    def test_initialize_from_config_with_default(self):
+        # No additional config given, check the default value here.
+        ascend_config = AscendSchedulerConfig.initialize_from_config(
+            self.basic_scheduler_config, {})
+        self.assertEqual(ascend_config.enable_chunked_prefill, False)
+        self.assertEqual(ascend_config.policy, "fcfs")
+        self.assertEqual(ascend_config.num_scheduler_steps, 1)
+        self.assertEqual(ascend_config.scheduler_cls,
+                         "vllm_ascend.core.scheduler.AscendScheduler")
+        self.assertEqual(ascend_config.max_num_encoder_input_tokens, 8192)
+        self.assertEqual(ascend_config.encoder_cache_size, 8192)
+
+    def test_initialize_from_config_with_override(self):
+        # test override
+        ascend_config = AscendSchedulerConfig.initialize_from_config(
+            self.basic_scheduler_config,
+            AscendSchedulerConfig(
+                enable_chunked_prefill=False,
+                policy="fcfs",
+                num_scheduler_steps=1,
+                scheduler_cls="vllm_ascend.core.scheduler.AscendScheduler",
+                max_num_batched_tokens=2048,
+            ),
+        )
+        self.assertEqual(ascend_config.enable_chunked_prefill, False)
+        self.assertEqual(ascend_config.policy, "fcfs")
+        self.assertEqual(ascend_config.num_scheduler_steps, 1)
+        self.assertEqual(ascend_config.scheduler_cls,
+                         "vllm_ascend.core.scheduler.AscendScheduler")
+        self.assertEqual(ascend_config.max_num_batched_tokens, 2048)
+        self.assertEqual(ascend_config.encoder_cache_size, 2048)
+
+    def test_not_implemented_policy(self):
+        with self.assertRaises(NotImplementedError) as context:
+            AscendSchedulerConfig.initialize_from_config(
+                self.basic_scheduler_config,
+                AscendSchedulerConfig(policy="custom_policy", ),
+            )
+        self.assertIn(
+            "currently AscendScheduler only supports fcfs policy",
+            str(context.exception),
+        )
+
+    def test_not_implemented_multimodal(self):
+        with self.assertRaises(NotImplementedError) as context:
+            AscendSchedulerConfig.initialize_from_config(
+                SchedulerConfig(is_multimodal_model=True), {})
+        self.assertIn("currently AscendScheduler only supports LLM models",
+                      str(context.exception))
+
+    def test_not_implemented_multi_step(self):
+        with self.assertRaises(NotImplementedError) as context:
+            AscendSchedulerConfig.initialize_from_config(
+                self.basic_scheduler_config,
+                AscendSchedulerConfig(num_scheduler_steps=2),
+            )
+        self.assertIn(
+            "currently AscendScheduler doesn't support multi-step",
+            str(context.exception),
+        )
+
+    def test_not_implemented_send_delta_data(self):
+        with self.assertRaises(NotImplementedError) as context:
+            AscendSchedulerConfig.initialize_from_config(
+                self.basic_scheduler_config,
+                AscendSchedulerConfig(send_delta_data=True))
+        self.assertIn(
+            "currently AscendScheduler doesn't support send_delta_data",
+            str(context.exception),
+        )
+
+    def test_not_implemented_delay_factor(self):
+        with self.assertRaises(NotImplementedError) as context:
+            AscendSchedulerConfig.initialize_from_config(
+                self.basic_scheduler_config,
+                AscendSchedulerConfig(delay_factor=1))
+        self.assertIn(
+            "currently AscendScheduler doesn't support scheduler_delay_factor",
+            str(context.exception),
+        )
+
+    def test_no_override(self):
+        ascend_config = AscendSchedulerConfig.initialize_from_config(
+            self.basic_scheduler_config, {})
+        self.assertEqual(ascend_config.max_num_encoder_input_tokens, 8192)
+        self.assertEqual(ascend_config.encoder_cache_size, 8192)