test: add delta-channel conformance wrappers for InMemory and SQLite savers

Runs the three new delta-channel conformance capabilities
(delta_channel_history, delta_channel_keepset, delta_channel_reconstruction)
against InMemorySaver and AsyncSqliteSaver. Guarded by importorskip so
they're skipped gracefully when checkpoint-conformance isn't installed.

Co-authored-by: Cursor <cursoragent@cursor.com>

libs/checkpoint-sqlite/tests/test_conformance_delta.py

@@ -0,0 +1,37 @@
+"""Run delta-channel conformance capabilities against AsyncSqliteSaver."""
+
+from __future__ import annotations
+
+import pytest
+
+pytest.importorskip(
+    "langgraph.checkpoint.conformance",
+    reason="langgraph-checkpoint-conformance not installed",
+)
+pytest.importorskip("aiosqlite", reason="aiosqlite not installed")
+
+from langgraph.checkpoint.conformance import validate  # noqa: E402
+from langgraph.checkpoint.conformance.initializer import checkpointer_test  # noqa: E402
+from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver  # noqa: E402
+
+
+@checkpointer_test(name="AsyncSqliteSaver")
+async def _sqlite_saver():
+    async with AsyncSqliteSaver.from_conn_string(":memory:") as saver:
+        yield saver
+
+
+@pytest.mark.asyncio
+async def test_delta_channel_conformance():
+    report = await validate(
+        _sqlite_saver,
+        capabilities={
+            "delta_channel_history",
+            "delta_channel_keepset",
+            "delta_channel_reconstruction",
+        },
+    )
+    for cap, result in report.results.items():
+        if result.passed is False:
+            details = "\n".join(result.failures or [])
+            pytest.fail(f"Capability {cap} failed:\n{details}")

libs/checkpoint/tests/test_conformance_delta.py

@@ -0,0 +1,37 @@
+"""Run delta-channel conformance capabilities against InMemorySaver."""
+
+from __future__ import annotations
+
+import asyncio
+
+import pytest
+
+pytest.importorskip(
+    "langgraph.checkpoint.conformance",
+    reason="langgraph-checkpoint-conformance not installed",
+)
+
+from langgraph.checkpoint.conformance import validate  # noqa: E402
+from langgraph.checkpoint.conformance.initializer import checkpointer_test  # noqa: E402
+from langgraph.checkpoint.memory import InMemorySaver  # noqa: E402
+
+
+@checkpointer_test(name="InMemorySaver")
+async def _mem_saver():
+    yield InMemorySaver()
+
+
+@pytest.mark.asyncio
+async def test_delta_channel_conformance():
+    report = await validate(
+        _mem_saver,
+        capabilities={
+            "delta_channel_history",
+            "delta_channel_keepset",
+            "delta_channel_reconstruction",
+        },
+    )
+    for cap, result in report.results.items():
+        if result.passed is False:
+            details = "\n".join(result.failures or [])
+            pytest.fail(f"Capability {cap} failed:\n{details}")