Drop-in. Upstream-tested.
fast-langraph runs LangGraph's own upstream test suite against its shimmed implementation. Zero failures. 85 pass, 3 skip for fixture/dependency reasons.
- LangGraph version
- 1.0.4
- Commit
- 4d01e69b
- Test date
- 2025-12-10
- Total tests
- 88
Tested modules
These upstream LangGraph test files pass against our shimmed implementation:
test_algo.py | Algorithm functions (apply_writes, prepare_next_tasks) |
test_channels.py | Channel implementations (LastValue, Topic, BinOp) |
test_config_async.py | Async configuration management |
test_deprecation.py | Deprecation warnings |
test_interrupt_migration.py | Interrupt serialization |
test_pydantic.py | Pydantic model support |
test_retry.py | Retry policies |
test_state.py | State schema validation |
test_tracing_interops.py | Tracing interoperability |
test_type_checking.py | Type checking |
What gets skipped (and why)
The 3 skipped test files require fixtures (sync_checkpointer), the optional trio async backend, or external infrastructure that isn't installed in the minimal test environment. None are compatibility failures — they're environment gaps. We re-run compatibility on every release.
Run it against your LangGraph version
python scripts/test_compatibility.py -v
# Or pin to a specific branch
python scripts/test_compatibility.py --branch v1.0.0 -vFound a compatibility issue on your LangGraph version? Open an issue — we treat parity as a P0.
Hit a LangGraph scaling wall?
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