community: add standard tests for Perplexity (#29534)

libs/community/tests/integration_tests/chat_models/test_perplexity.py

@@ -0,0 +1,33 @@
+"""Standard LangChain interface tests"""
+
+from typing import Type
+
+import pytest
+from langchain_core.language_models import BaseChatModel
+from langchain_tests.integration_tests import ChatModelIntegrationTests
+
+from langchain_community.chat_models import ChatPerplexity
+
+
+class TestPerplexityStandard(ChatModelIntegrationTests):
+    @property
+    def chat_model_class(self) -> Type[BaseChatModel]:
+        return ChatPerplexity
+
+    @property
+    def chat_model_params(self) -> dict:
+        return {"model": "sonar"}
+
+    @property
+    def returns_usage_metadata(self) -> bool:
+        # TODO: add usage metadata and delete this property
+        # https://docs.perplexity.ai/api-reference/chat-completions#response-usage
+        return False
+
+    @pytest.mark.xfail(reason="TODO: handle in integration.")
+    def test_double_messages_conversation(self, model: BaseChatModel) -> None:
+        super().test_double_messages_conversation(model)
+
+    @pytest.mark.xfail(reason="Raises 400: Custom stop words not supported.")
+    def test_stop_sequence(self, model: BaseChatModel) -> None:
+        super().test_stop_sequence(model)