test(checkpoint): run the delta conformance suite against InMemorySaver in CI

The conformance self-test asserted only the base capabilities, and the
libs/checkpoint copy of the delta conformance run always skips in CI, so
no CI job checked InMemorySaver's delta history against the suite. The
self-test now asserts every capability InMemorySaver implements, and the
skipped copy is gone.

libs/checkpoint-conformance/tests/test_validate_memory.py

@@ -14,8 +14,8 @@ async def memory_checkpointer():
 
 
 @pytest.mark.asyncio
-async def test_validate_memory_base():
-    """InMemorySaver passes all base capability tests."""
+async def test_validate_memory():
+    """InMemorySaver passes the tests of every capability it implements."""
     report = await validate(memory_checkpointer)
     report.print_report()
-    assert report.passed_all_base(), f"Base tests failed: {report.to_dict()}"
+    assert report.passed_all(), f"Capability tests failed: {report.to_dict()}"

libs/checkpoint/tests/test_conformance_delta.py

@@ -1,37 +0,0 @@
-"""Run delta-channel conformance capabilities against InMemorySaver."""
-
-from __future__ import annotations
-
-import pytest
-
-conformance = pytest.importorskip(
-    "langgraph.checkpoint.conformance",
-    reason="langgraph-checkpoint-conformance not installed",
-)
-
-
-@pytest.mark.asyncio
-async def test_delta_channel_conformance():
-    # Imported inside the test: the module-level importorskip above is what
-    # makes these safe, so they cannot move to the top of the file.
-    from langgraph.checkpoint.conformance import validate  # noqa: PLC0415
-    from langgraph.checkpoint.conformance.initializer import (  # noqa: PLC0415
-        checkpointer_test,
-    )
-
-    from langgraph.checkpoint.memory import InMemorySaver  # noqa: PLC0415
-
-    @checkpointer_test(name="InMemorySaver")
-    async def mem_saver():
-        yield InMemorySaver()
-
-    report = await validate(
-        mem_saver,
-        capabilities={
-            "delta_channel_history",
-        },
-    )
-    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}")