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TestSyncAsyncInterop Class — langchain Architecture

Architecture documentation for the TestSyncAsyncInterop class in test_wrap_model_call.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  78211736_7c97_19d0_14c2_d2b492c194dd["TestSyncAsyncInterop"]
  949c7cf4_56fe_f3b4_cd89_9631a7e9cb1e["AgentMiddleware"]
  78211736_7c97_19d0_14c2_d2b492c194dd -->|extends| 949c7cf4_56fe_f3b4_cd89_9631a7e9cb1e
  573473e5_eb93_a7d7_84ba_c975071c09af["test_wrap_model_call.py"]
  78211736_7c97_19d0_14c2_d2b492c194dd -->|defined in| 573473e5_eb93_a7d7_84ba_c975071c09af
  63b1c906_416a_cecb_4300_aac3c338b4fe["test_sync_invoke_with_only_async_middleware_raises_error()"]
  78211736_7c97_19d0_14c2_d2b492c194dd -->|method| 63b1c906_416a_cecb_4300_aac3c338b4fe
  a19c0a5c_ca2b_3869_ab7a_70d066eca849["test_sync_invoke_with_mixed_middleware()"]
  78211736_7c97_19d0_14c2_d2b492c194dd -->|method| a19c0a5c_ca2b_3869_ab7a_70d066eca849

Relationship Graph

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py lines 1466–1532

class TestSyncAsyncInterop:
    """Test sync/async interoperability."""

    def test_sync_invoke_with_only_async_middleware_raises_error(self) -> None:
        """Test that sync invoke with only async middleware raises error."""

        class AsyncOnlyMiddleware(AgentMiddleware):
            async def awrap_model_call(
                self,
                request: ModelRequest,
                handler: Callable[[ModelRequest], Awaitable[ModelResponse]],
            ) -> ModelCallResult:
                return await handler(request)

        agent = create_agent(
            model=FakeToolCallingModel(),
            tools=[],
            system_prompt="You are a helpful assistant.",
            middleware=[AsyncOnlyMiddleware()],
        )

        with pytest.raises(NotImplementedError):
            agent.invoke({"messages": [HumanMessage("hello")]})

    def test_sync_invoke_with_mixed_middleware(self) -> None:
        """Test that sync invoke works with mixed sync/async middleware when sync versions exist."""
        calls = []

        class MixedMiddleware(AgentMiddleware):
            @override
            def before_model(self, state: AgentState[Any], runtime: Runtime[Any]) -> None:
                calls.append("MixedMiddleware.before_model")

            @override
            async def abefore_model(self, state: AgentState[Any], runtime: Runtime[Any]) -> None:
                calls.append("MixedMiddleware.abefore_model")

            def wrap_model_call(
                self,
                request: ModelRequest,
                handler: Callable[[ModelRequest], ModelResponse],
            ) -> ModelCallResult:
                calls.append("MixedMiddleware.wrap_model_call")
                return handler(request)

            async def awrap_model_call(
                self,
                request: ModelRequest,
                handler: Callable[[ModelRequest], Awaitable[ModelResponse]],
            ) -> ModelCallResult:
                calls.append("MixedMiddleware.awrap_model_call")
                return await handler(request)

        agent = create_agent(
            model=FakeToolCallingModel(),
            tools=[],
            system_prompt="You are a helpful assistant.",
            middleware=[MixedMiddleware()],
        )

        agent.invoke({"messages": [HumanMessage("hello")]})

        # In sync mode, only sync methods should be called
        assert calls == [
            "MixedMiddleware.before_model",
            "MixedMiddleware.wrap_model_call",
        ]

Defined In

Extends

Source

Frequently Asked Questions

What is the TestSyncAsyncInterop class?
TestSyncAsyncInterop is a class in the langchain codebase, defined in libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py.
Where is TestSyncAsyncInterop defined?
TestSyncAsyncInterop is defined in libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py at line 1466.
What does TestSyncAsyncInterop extend?
TestSyncAsyncInterop extends AgentMiddleware.

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