Harrison/improve memory (#432)

add AI prefix

add new type of memory

Co-authored-by: Jason <chisanch@usc.edu>

tests/unit_tests/chains/test_conversation.py

@@ -12,6 +12,13 @@ from langchain.prompts.prompt import PromptTemplate
 from tests.unit_tests.llms.fake_llm import FakeLLM
 
 
+def test_memory_ai_prefix() -> None:
+    """Test that ai_prefix in the memory component works."""
+    memory = ConversationBufferMemory(memory_key="foo", ai_prefix="Assistant")
+    memory.save_context({"input": "bar"}, {"output": "foo"})
+    assert memory.buffer == "\nHuman: bar\nAssistant: foo"
+
+
 def test_conversation_chain_works() -> None:
     """Test that conversation chain works in basic setting."""
     llm = FakeLLM()
@@ -42,6 +49,7 @@ def test_conversation_chain_errors_bad_variable() -> None:
     "memory",
     [
         ConversationBufferMemory(memory_key="baz"),
+        ConversationalBufferWindowMemory(memory_key="baz"),
         ConversationSummaryMemory(llm=FakeLLM(), memory_key="baz"),
     ],
 )
@@ -81,7 +89,7 @@ def test_clearing_conversation_memory(memory: Memory) -> None:
     """Test clearing the conversation memory."""
     # This is a good input because the input is not the same as baz.
     good_inputs = {"foo": "bar", "baz": "foo"}
-    # This is a good output because these is one variable.
+    # This is a good output because there is one variable.
     good_outputs = {"bar": "foo"}
     memory.save_context(good_inputs, good_outputs)