langgraph/libs/checkpoint-conformance/README.md

langgraph-checkpoint-conformance

Conformance test suite for LangGraph checkpointer implementations.

Validates that a BaseCheckpointSaver subclass correctly implements the checkpoint storage contract — blob round-trips, metadata preservation, namespace isolation, incremental channel updates, and more.

Installation

pip install langgraph-checkpoint-conformance

Quick start

Register your checkpointer with @checkpointer_test and run validate():

import asyncio
from langgraph.checkpoint.conformance import checkpointer_test, validate

@checkpointer_test(name="MyCheckpointer")
async def my_checkpointer():
    saver = MyCheckpointer(...)
    yield saver
    # cleanup runs after yield

async def main():
    report = await validate(my_checkpointer)
    report.print_report()
    assert report.passed_all_base()

asyncio.run(main())

Or in a pytest test:

import pytest
from langgraph.checkpoint.conformance import checkpointer_test, validate

@checkpointer_test(name="MyCheckpointer")
async def my_checkpointer():
    yield MyCheckpointer(...)

@pytest.mark.asyncio
async def test_conformance():
    report = await validate(my_checkpointer)
    report.print_report()
    assert report.passed_all_base()

Capabilities

The suite tests base capabilities (required) and extended capabilities (optional, auto-detected):

Capability	Required	Method
put	yes	aput
put_writes	yes	aput_writes
get_tuple	yes	aget_tuple
list	yes	alist
delete_thread	yes	adelete_thread
delete_for_runs	no	adelete_for_runs
copy_thread	no	acopy_thread
prune	no	aprune
delta_channel_history	no	aget_delta_channel_history
delta_channel_keepset	no	aget_delta_channel_keepset
delta_channel_reconstruction	no	aput

Extended capabilities are detected by checking whether the method is overridden from BaseCheckpointSaver. If not overridden, those tests are skipped.

Options

Progress output

from langgraph.checkpoint.conformance.report import ProgressCallbacks

# Dot-style progress (. per pass, F per fail)
report = await validate(my_checkpointer, progress=ProgressCallbacks.default())

# Verbose (per-test names + stacktraces on failure)
report = await validate(my_checkpointer, progress=ProgressCallbacks.verbose())

Skip capabilities

@checkpointer_test(name="MyCheckpointer", skip_capabilities={"prune"})
async def my_checkpointer():
    yield MyCheckpointer(...)

Run specific capabilities

report = await validate(my_checkpointer, capabilities={"put", "list"})

Lifespan (one-time setup/teardown)

For expensive setup like database creation:

async def db_lifespan():
    await create_database()
    yield
    await drop_database()

@checkpointer_test(name="PostgresSaver", lifespan=db_lifespan)
async def pg_checkpointer():
    async with PostgresSaver.from_conn_string(CONN_STRING) as saver:
        yield saver