[Spec Decode][CI] Add e2e test for examples/spec_decode.py and prevent breaking Acceptance Length

.buildkite/test-pipeline.yaml

@@ -316,6 +316,7 @@ steps:
     - python3 offline_inference/basic/embed.py
     - python3 offline_inference/basic/score.py
     - VLLM_USE_V1=0 python3 offline_inference/profiling.py --model facebook/opt-125m run_num_steps --num-steps 2
+    - python3 offline_inference/spec_decode.py --test --method eagle --num_spec_tokens 3 --dataset-name hf --dataset-path philschmid/mt-bench --num-prompts 80 --temp 0 --top-p 1.0 --top-k -1 --tp 1 --enable-chunked-prefill
 
 - label: Platform Tests (CUDA) # 4min
   timeout_in_minutes: 15

examples/offline_inference/spec_decode.py

@@ -49,6 +49,7 @@ def get_custom_mm_prompts(num_prompts):
 def parse_args():
     parser = FlexibleArgumentParser()
     add_dataset_parser(parser)
+    parser.add_argument("--test", action="store_true")
     parser.add_argument(
         "--method",
         type=str,
@@ -72,8 +73,7 @@ def parse_args():
     return parser.parse_args()
 
 
-def main():
-    args = parse_args()
+def main(args):
     args.endpoint_type = "openai-chat"
 
     model_dir = args.model_dir
@@ -194,6 +194,34 @@ def main():
         acceptance_rate = acceptance_counts[i] / num_drafts if num_drafts > 0 else 0
         print(f"acceptance at token {i}: {acceptance_rate:.2f}")
 
+    return acceptance_length
+
 
 if __name__ == "__main__":
-    main()
+    args = parse_args()
+    acceptance_length = main(args)
+
+    if args.test:
+        # takes ~30s to run on 1xH100
+        assert args.method == "eagle"
+        assert args.tp == 1
+        assert args.num_spec_tokens == 3
+        assert args.dataset_path == "philschmid/mt-bench"
+        assert args.num_prompts == 80
+        assert args.temp == 0
+        assert args.top_p == 1.0
+        assert args.top_k == -1
+        assert args.enable_chunked_prefill
+
+        # check acceptance length is within 1% of expected value
+        rtol = 0.01
+        expected_acceptance_length = 2.29
+        assert (
+            acceptance_length <= (1 + rtol) * expected_acceptance_length
+            and acceptance_length >= (1 - rtol) * expected_acceptance_length
+        ), (
+            f"acceptance_length {acceptance_length} is not \
+            within {rtol * 100}% of {expected_acceptance_length}"
+        )
+
+        print("Test passed!")