[Bugfix / Core] Prefix Caching Guards (merged with main) (#4846)

Co-authored-by: rsnm2 <rshaw@neuralmagic.com>
Co-authored-by: Robert Shaw <114415538+robertgshaw2-neuralmagic@users.noreply.github.com>

tests/prefix_caching/test_disable_sliding_window.py

@@ -0,0 +1,44 @@
+"""Compare the with and without prefix caching.
+
+Run `pytest tests/prefix_caching/test_prefix_caching.py`.
+"""
+import pytest
+
+from tests.conftest import cleanup
+from vllm import LLM
+
+MODEL_LEN_LEN = [
+    # Example models with sliding window.
+    ("bigcode/starcoder2-3b", 4096, 16384),
+    # ("mistralai/Mistral-7B-v0.1", 4096, 32768), << OOM in CI
+
+    # Confirm model with sliding window works.
+    # config has "use_sliding_window": false
+    ("Qwen/Qwen1.5-0.5B-Chat", 32768, 32768),
+    # config has no sliding window attribute.
+    ("TinyLlama/TinyLlama-1.1B-Chat-v1.0", 2048, 2048),
+]
+
+
+@pytest.mark.parametrize("model_len_len", MODEL_LEN_LEN)
+def test_disable_sliding_window(model_len_len, ):
+    model, sliding_len, full_len = model_len_len
+    vllm_disabled_model = LLM(model, disable_sliding_window=True)
+    vllm_disabled_model.generate("Hi my name is")
+    model_config = vllm_disabled_model.llm_engine.model_config
+    assert model_config.max_model_len == sliding_len, (
+        "Max len expected to equal sliding_len of %s, but got %s", sliding_len,
+        model_config.max_model_len)
+
+    del vllm_disabled_model
+    cleanup()
+
+    vllm_enabled_model = LLM(model, disable_sliding_window=False)
+    vllm_enabled_model.generate("Hi my name is")
+    model_config = vllm_enabled_model.llm_engine.model_config
+    assert model_config.max_model_len == full_len, (
+        "Max len expected to equal full_len of %s, but got %s", full_len,
+        model_config.max_model_len)
+
+    del vllm_enabled_model
+    cleanup()