diff --git a/test/registered/scheduler/test_prefill_adder.py b/test/registered/scheduler/test_prefill_adder.py
index 0a7ac5217..f2fe6d193 100644
--- a/test/registered/scheduler/test_prefill_adder.py
+++ b/test/registered/scheduler/test_prefill_adder.py
@@ -3,7 +3,7 @@ from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
 from sglang.srt.managers.schedule_batch import Req
-from sglang.srt.managers.schedule_policy import PrefillAdder
+from sglang.srt.managers.schedule_policy import AddReqResult, PrefillAdder
 from sglang.test.ci.ci_register import register_amd_ci, register_cuda_ci
 from sglang.test.test_utils import CustomTestCase
 
@@ -79,8 +79,8 @@ class TestPrefillAdder(CustomTestCase):
         req.finished.return_value = False
         return req
 
-    def create_adder(self, running_batch):
-        return PrefillAdder(
+    def create_adder(self, running_batch, **kwargs):
+        defaults = dict(
             page_size=1,
             tree_cache=self.mock_tree_cache,
             token_to_kv_pool_allocator=self.mock_token_allocator,
@@ -91,6 +91,8 @@ class TestPrefillAdder(CustomTestCase):
             mixed_with_decode_tokens=0,
             priority_scheduling_preemption_threshold=0,
         )
+        defaults.update(kwargs)
+        return PrefillAdder(**defaults)
 
     def test_preempt_success_high_priority_values_first(self):
         params = [
@@ -350,6 +352,96 @@ class TestPrefillAdder(CustomTestCase):
         )  # 50 + 75 + 100 + 125 + 125 - 100 - 125 = 250
         self.assertEqual(running_batch.release_req.call_count, 2)
 
+    def test_mixed_chunk_prefill_budgets(self):
+        self.mock_token_allocator.available_size.return_value = 1000
+
+        decode_reqs = [
+            self.create_mock_req(f"decode_{i}", priority=0, max_new_tokens=50)
+            for i in range(8)
+        ]
+        running_batch = self.create_running_batch(decode_reqs)
+
+        adder = self.create_adder(
+            running_batch,
+            rem_input_tokens=200,
+            rem_chunk_tokens=64,
+            mixed_with_decode_tokens=len(decode_reqs),
+        )
+
+        self.assertEqual(adder.rem_input_tokens, 192)  # 200 - 8
+        self.assertEqual(adder.rem_chunk_tokens, 56)  # 64 - 8
+        self.assertEqual(adder.rem_total_token_offset, 408)  # 8 + 8 * 50
+        self.assertEqual(adder.cur_rem_token_offset, 8)
+        self.assertEqual(adder.budget_state(), AddReqResult.CONTINUE)
+
+        # Add a prefill that exactly consumes the chunk budget
+        req1 = self.create_mock_req("req1", priority=0, max_new_tokens=64)
+        req1.extend_input_len = 56
+        req1.host_hit_length = 0
+        req1.prefix_indices = []
+        req1.fill_ids = list(range(56))
+        req1.last_node = MagicMock()
+        req1.sampling_params.ignore_eos = False
+
+        result1 = adder.add_one_req(
+            req1, has_chunked_req=False, truncation_align_size=None
+        )
+
+        self.assertEqual(len(adder.can_run_list), 1)
+        self.assertEqual(adder.rem_chunk_tokens, 0)  # 56 - 56
+        self.assertEqual(adder.rem_input_tokens, 136)  # 192 - 56
+        self.assertEqual(result1, AddReqResult.OTHER)
+
+        # 3 decode requests finished
+        remaining_decode_reqs = decode_reqs[3:]
+        running_batch2 = self.create_running_batch(remaining_decode_reqs)
+
+        adder2 = self.create_adder(
+            running_batch2,
+            rem_input_tokens=200,
+            rem_chunk_tokens=64,
+            mixed_with_decode_tokens=len(remaining_decode_reqs),
+        )
+
+        self.assertEqual(adder2.rem_input_tokens, 195)  # 200 - 5
+        self.assertEqual(adder2.rem_chunk_tokens, 59)  # 64 - 5
+        self.assertEqual(adder2.rem_total_token_offset, 255)  # 5 + 5 * 50
+        self.assertEqual(adder2.budget_state(), AddReqResult.CONTINUE)
+
+        # Same prefill no longer exhausts the chunk budget
+        req2 = self.create_mock_req("req2", priority=0, max_new_tokens=64)
+        req2.extend_input_len = 56
+        req2.host_hit_length = 0
+        req2.prefix_indices = []
+        req2.fill_ids = list(range(56))
+        req2.last_node = MagicMock()
+        req2.sampling_params.ignore_eos = False
+
+        result2 = adder2.add_one_req(
+            req2, has_chunked_req=False, truncation_align_size=None
+        )
+
+        self.assertEqual(len(adder2.can_run_list), 1)
+        self.assertEqual(adder2.rem_chunk_tokens, 3)  # 59 - 56 = 3 remaining
+        self.assertEqual(result2, AddReqResult.CONTINUE)
+
+        # Fit last small prefill request
+        req3 = self.create_mock_req("req3", priority=0, max_new_tokens=16)
+        req3.extend_input_len = 3
+        req3.host_hit_length = 0
+        req3.prefix_indices = []
+        req3.fill_ids = list(range(3))
+        req3.last_node = MagicMock()
+        req3.sampling_params.ignore_eos = False
+
+        result3 = adder2.add_one_req(
+            req3, has_chunked_req=False, truncation_align_size=None
+        )
+
+        self.assertEqual(len(adder2.can_run_list), 2)
+        self.assertEqual(adder2.rem_chunk_tokens, 0)  # 3 - 3 = 0
+        self.assertEqual(result3, AddReqResult.OTHER)
+
 
 if __name__ == "__main__":
     unittest.main()