Harrison/improve memory (#432)

add AI prefix

add new type of memory

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

tests/integration_tests/chains/test_memory.py

@@ -0,0 +1,31 @@
+"""Test memory functionality."""
+from langchain.chains.conversation.memory import ConversationSummaryBufferMemory
+from tests.unit_tests.llms.fake_llm import FakeLLM
+
+
+def test_summary_buffer_memory_no_buffer_yet() -> None:
+    """Test ConversationSummaryBufferMemory when no inputs put in buffer yet."""
+    memory = ConversationSummaryBufferMemory(llm=FakeLLM(), memory_key="baz")
+    output = memory.load_memory_variables({})
+    assert output == {"baz": ""}
+
+
+def test_summary_buffer_memory_buffer_only() -> None:
+    """Test ConversationSummaryBufferMemory when only buffer."""
+    memory = ConversationSummaryBufferMemory(llm=FakeLLM(), memory_key="baz")
+    memory.save_context({"input": "bar"}, {"output": "foo"})
+    assert memory.buffer == ["Human: bar\nAI: foo"]
+    output = memory.load_memory_variables({})
+    assert output == {"baz": "Human: bar\nAI: foo"}
+
+
+def test_summary_buffer_memory_summary() -> None:
+    """Test ConversationSummaryBufferMemory when only buffer."""
+    memory = ConversationSummaryBufferMemory(
+        llm=FakeLLM(), memory_key="baz", max_token_limit=13
+    )
+    memory.save_context({"input": "bar"}, {"output": "foo"})
+    memory.save_context({"input": "bar1"}, {"output": "foo1"})
+    assert memory.buffer == ["Human: bar1\nAI: foo1"]
+    output = memory.load_memory_variables({})
+    assert output == {"baz": "foo\nHuman: bar1\nAI: foo1"}