[CI] Add PPL test for generation models (#24485)

Signed-off-by: wang.yuqi <noooop@126.com>

tests/models/language/generation_ppl_test/test_gemma.py

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import pytest
+
+from tests.models.utils import GenerateModelInfo
+
+from .ppl_utils import wikitext_ppl_test
+
+MODELS = [
+    GenerateModelInfo("google/gemma-2b"),
+    GenerateModelInfo("google/gemma-2-2b"),
+    GenerateModelInfo("google/gemma-3-4b-it"),
+]
+
+
+@pytest.mark.parametrize("model_info", MODELS)
+def test_ppl(hf_runner, vllm_runner, model_info: GenerateModelInfo):
+    wikitext_ppl_test(hf_runner, vllm_runner, model_info)