feat: add tests for chat message history class

integration.cloudbuild.yaml

@@ -22,3 +22,9 @@ steps:
     name: python:3.11
     entrypoint: python
     args: ["-m", "pytest"]
+    env:
+      - 'REDIS_URL=$_REDIS_URL'
+
+options:
+  pool:
+    name: '$_WORKER_POOL'

src/langchain_google_memorystore_redis/__init__.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from langchain_google_memorystore_redis.chat_message_history import MemorystoreChatMessageHistory
+from langchain_google_memorystore_redis.chat_message_history import (
+    MemorystoreChatMessageHistory,
+)
 
 __all__ = ["MemorystoreChatMessageHistory"]

src/langchain_google_memorystore_redis/chat_message_history.py

@@ -13,15 +13,11 @@
 # limitations under the License.
 
 import json
-import redis
 from typing import List, Optional
 
+import redis
 from langchain_core.chat_history import BaseChatMessageHistory
-from langchain_core.messages import (
-    BaseMessage,
-    message_to_dict,
-    messages_from_dict,
-)
+from langchain_core.messages import BaseMessage, message_to_dict, messages_from_dict
 
 
 class MemorystoreChatMessageHistory(BaseChatMessageHistory):
@@ -46,15 +42,21 @@ def __init__(
         self._redis = client
         self._key = session_id
         self._ttl = ttl
+        self._encoding = client.get_encoder().encoding
 
     @property
-    def messages(self) -> List[BaseMessage]:
+    def messages(self) -> List[BaseMessage]:  # type: ignore
         """Retrieve all messages chronologically stored in this session."""
         all_elements = self._redis.lrange(self._key, 0, -1)
-        messages = messages_from_dict(
-            [json.loads(e.decode("utf-8")) for e in all_elements]
-        )
-        return messages
+
+        loaded_messages = []
+        if isinstance(all_elements, list):
+            loaded_messages = messages_from_dict(
+                [json.loads(e.decode(self._encoding)) for e in all_elements]
+            )
+        else:
+            raise RuntimeError("redis-py returns result of unexpected type")
+        return loaded_messages
 
     def add_message(self, message: BaseMessage) -> None:
         """Append one message to this session."""

tests/test_chat_message_history.py

@@ -0,0 +1,67 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import os
+import uuid
+
+import redis
+from langchain_core.messages import AIMessage, BaseMessage, HumanMessage
+
+from langchain_google_memorystore_redis import MemorystoreChatMessageHistory
+
+
+def test_redis_multiple_sessions() -> None:
+    client = redis.from_url(get_env_var("REDIS_URL", "URL of the Redis instance"))
+
+    session_id1 = uuid.uuid4().hex
+    history1 = MemorystoreChatMessageHistory(
+        client=client,
+        session_id=session_id1,
+    )
+    session_id2 = uuid.uuid4().hex
+    history2 = MemorystoreChatMessageHistory(
+        client=client,
+        session_id=session_id2,
+    )
+
+    history1.add_ai_message("Hey! I am AI!")
+    history1.add_user_message("Hey! I am human!")
+    history2.add_user_message("Hey! I am human in another session!")
+    messages1 = history1.messages
+    messages2 = history2.messages
+
+    assert len(messages1) == 2
+    assert len(messages2) == 1
+    assert isinstance(messages1[0], AIMessage)
+    assert messages1[0].content == "Hey! I am AI!"
+    assert isinstance(messages1[1], HumanMessage)
+    assert messages1[1].content == "Hey! I am human!"
+    assert isinstance(messages2[0], HumanMessage)
+    assert messages2[0].content == "Hey! I am human in another session!"
+
+    history1.clear()
+    assert len(history1.messages) == 0
+    assert len(history2.messages) == 1
+
+    history2.clear()
+    assert len(history1.messages) == 0
+    assert len(history2.messages) == 0
+
+
+def get_env_var(key: str, desc: str) -> str:
+    v = os.environ.get(key)
+    if v is None:
+        raise ValueError(f"Must set env var {key} to: {desc}")
+    return v