Add vllm bench [latency, throughput] CLI commands (#16508)

Signed-off-by: mgoin <mgoin64@gmail.com>

tests/benchmarks/test_serve_cli.py

@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: Apache-2.0
+import subprocess
+
+import pytest
+
+from ..utils import RemoteOpenAIServer
+
+MODEL_NAME = "meta-llama/Llama-3.2-1B-Instruct"
+
+
+@pytest.fixture(scope="module")
+def server():
+    args = [
+        "--max-model-len", "1024", "--enforce-eager", "--load-format", "dummy"
+    ]
+
+    with RemoteOpenAIServer(MODEL_NAME, args) as remote_server:
+        yield remote_server
+
+
+@pytest.mark.benchmark
+def test_bench_serve(server):
+    command = [
+        "vllm",
+        "bench",
+        "serve",
+        "--model",
+        MODEL_NAME,
+        "--host",
+        server.host,
+        "--port",
+        str(server.port),
+        "--random-input-len",
+        "32",
+        "--random-output-len",
+        "4",
+        "--num-prompts",
+        "5",
+    ]
+    result = subprocess.run(command, capture_output=True, text=True)
+    print(result.stdout)
+    print(result.stderr)
+
+    assert result.returncode == 0, f"Benchmark failed: {result.stderr}"