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test_model_fallback_middleware_initialization() — langchain Function Reference

Architecture documentation for the test_model_fallback_middleware_initialization() function in test_model_fallback.py from the langchain codebase.

Function python LangChainCore LanguageModelBase

Entity Profile

Dependency Diagram

graph TD
  3cac54ce_cc46_38be_068f_f3b46c12ba31["test_model_fallback_middleware_initialization()"]
  c6372e75_e4e3_ed20_8230_4be219762f0f["test_model_fallback.py"]
  3cac54ce_cc46_38be_068f_f3b46c12ba31 -->|defined in| c6372e75_e4e3_ed20_8230_4be219762f0f
  style 3cac54ce_cc46_38be_068f_f3b46c12ba31 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_fallback.py lines 369–381

def test_model_fallback_middleware_initialization() -> None:
    """Test ModelFallbackMiddleware initialization."""
    # Test with no models - now a TypeError (missing required argument)
    with pytest.raises(TypeError):
        ModelFallbackMiddleware()  # type: ignore[call-arg]

    # Test with one fallback model (valid)
    middleware = ModelFallbackMiddleware(FakeToolCallingModel())
    assert len(middleware.models) == 1

    # Test with multiple fallback models
    middleware = ModelFallbackMiddleware(FakeToolCallingModel(), FakeToolCallingModel())
    assert len(middleware.models) == 2

Domain

Subdomains

Defined In

Source

Frequently Asked Questions

What does test_model_fallback_middleware_initialization() do?
test_model_fallback_middleware_initialization() is a function in the langchain codebase, defined in libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_fallback.py.
Where is test_model_fallback_middleware_initialization() defined?
test_model_fallback_middleware_initialization() is defined in libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_fallback.py at line 369.

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