Files
langchain/libs/standard-tests
Christophe Bornet 1de100f278 chore(infra): bump mypy to 2.1 and unify type-check config across the monorepo (#36470)
Originally a narrow bump of mypy to `1.20` in four packages. Expanded to
get the whole monorepo onto a single, current mypy and a consistent
type-check configuration, so contributors no longer hit different mypy
versions and divergent behavior depending on which package they touch.

### What changed

- **Unified the mypy pin to `>=2.1.0,<2.2.0`** in every mypy-using
package (6 libs + 14 partners), replacing the previously scattered pins
(`1.10`/`1.17`/`1.18`/`1.19`/`1.20`, with assorted upper bounds).
- **Unified the `[tool.mypy]` base per tier:**
- libs: `plugins = ["pydantic.mypy"]`, `strict = true`,
`enable_error_code = "deprecated"`, `warn_unreachable = true`
  - partners: `disallow_untyped_defs = true`
- Normalized style (`disallow_untyped_defs = "True"` string → bool,
quote/key consistency).
- **Fixed the 20 real errors** mypy 2.1 surfaces: `redundant-cast` from
improved narrowing (`core`, `langchain-classic`), a `var-annotated` for
`_LOGGED`, a return-type widening in `langchain-groq`'s
`_convert_from_v1_to_groq` (it can legitimately return a bare `str`),
and stale `type-arg`/`unused-ignore` in `langchain-model-profiles`
tests.

### Deliberate non-uniformity (documented inline in the relevant
`pyproject.toml`s)

Going fully byte-identical would surface ~196 additional errors that are
*not* real bugs, so two settings are kept package-appropriate:

- **`warn_unreachable`** is enabled on every strict lib **except
`core`**, where it false-flags intentional defensive code — including
the SSRF / IP-policy guards in `_security/` — as unreachable.
- **`pydantic.mypy` plugin** is used only on `anthropic` and
`perplexity` (their code is authored against it and reports ~99/~132
errors without it). It is *not* added to the other partners, where it
only flags the public alias constructor API (e.g. `ChatGroq(model=...)`)
in tests rather than finding bugs.
- **`ollama`** is left on its `ty` type checker; it does not use mypy.

---------

Co-authored-by: Mason Daugherty <github@mdrxy.com>
2026-06-11 00:24:59 -04:00
..

🦜🔗 langchain-tests

PyPI - Version PyPI - License PyPI - Downloads Twitter

Looking for the JS/TS version? Check out LangChain.js.

Quick Install

pip install langchain-tests

🤔 What is this?

This is a testing library for LangChain integrations. It contains the base classes for a standard set of tests.

📖 Documentation

For full documentation, see the API reference.

📕 Releases & Versioning

See our Releases and Versioning policies.

We encourage pinning your version to a specific version in order to avoid breaking your CI when we publish new tests. We recommend upgrading to the latest version periodically to make sure you have the latest tests.

Not pinning your version will ensure you always have the latest tests, but it may also break your CI if we introduce tests that your integration doesn't pass.

💁 Contributing

As an open-source project in a rapidly developing field, we are extremely open to contributions, whether it be in the form of a new feature, improved infrastructure, or better documentation.

For detailed information on how to contribute, see the Contributing Guide.

Usage

To add standard tests to an integration package (e.g., for a chat model), you need to create

  1. A unit test class that inherits from ChatModelUnitTests
  2. An integration test class that inherits from ChatModelIntegrationTests

tests/unit_tests/test_standard.py:

"""Standard LangChain interface tests"""

from typing import Type

import pytest
from langchain_core.language_models import BaseChatModel
from langchain_tests.unit_tests import ChatModelUnitTests

from langchain_parrot_chain import ChatParrotChain


class TestParrotChainStandard(ChatModelUnitTests):
    @pytest.fixture
    def chat_model_class(self) -> Type[BaseChatModel]:
        return ChatParrotChain

tests/integration_tests/test_standard.py:

"""Standard LangChain interface tests"""

from typing import Type

import pytest
from langchain_core.language_models import BaseChatModel
from langchain_tests.integration_tests import ChatModelIntegrationTests

from langchain_parrot_chain import ChatParrotChain


class TestParrotChainStandard(ChatModelIntegrationTests):
    @pytest.fixture
    def chat_model_class(self) -> Type[BaseChatModel]:
        return ChatParrotChain

Reference

The following fixtures are configurable in the test classes. Anything not marked as required is optional.

  • chat_model_class (required): The class of the chat model to be tested
  • chat_model_params: The keyword arguments to pass to the chat model constructor
  • chat_model_has_tool_calling: Whether the chat model can call tools. By default, this is set to hasattr(chat_model_class, 'bind_tools)
  • chat_model_has_structured_output: Whether the chat model can structured output. By default, this is set to hasattr(chat_model_class, 'with_structured_output')