[Misc] Add quantization config support for speculative model. (#7343)

tests/spec_decode/e2e/test_integration.py

@@ -42,3 +42,51 @@ def test_spec_decode_cuda_graph(baseline_llm_generator, test_llm_generator,
         max_output_len=output_len,
         force_output_len=True,
     )
+
+
+@pytest.mark.parametrize(
+    "common_llm_kwargs",
+    [{
+        "model": "JackFram/llama-160m",
+
+        # Skip cuda graph recording for fast test.
+        "enforce_eager": True,
+
+        # Required for spec decode.
+        "use_v2_block_manager": True,
+    }])
+@pytest.mark.parametrize("per_test_common_llm_kwargs", [
+    {
+        "speculative_model": "LnL-AI/TinyLlama-1.1B-Chat-v1.0-GPTQ-4bit",
+        "num_speculative_tokens": 5,
+    },
+])
+@pytest.mark.parametrize(
+    "test_llm_kwargs",
+    [
+        # Explicitly specify draft model quantization
+        {
+            "speculative_model_quantization": "gptq",
+        },
+        # Explicitly specify GPTQ-based draft model to use marlin quantization
+        {
+            "speculative_model_quantization": "marlin",
+        },
+        # Not explicitly specify draft model quantization
+        {
+            "speculative_model_quantization": None,
+        },
+    ])
+@pytest.mark.parametrize("baseline_llm_kwargs", [{}])
+@pytest.mark.parametrize("batch_size", [2])
+@pytest.mark.parametrize("seed", [1])
+def test_speculative_model_quantization_config(baseline_llm_generator,
+                                               test_llm_generator,
+                                               batch_size: int):
+    """Verify spec decode works well with draft model quantization configs.
+    """
+    run_greedy_equality_correctness_test(baseline_llm_generator,
+                                         test_llm_generator,
+                                         batch_size,
+                                         max_output_len=32,
+                                         force_output_len=True)