test_chat_prompt_template_message_class_tuples_partial_variables() — langchain Function Reference

Source Code

libs/core/tests/unit_tests/prompts/test_chat.py lines 444–458

def test_chat_prompt_template_message_class_tuples_partial_variables() -> None:
    """Test message class tuples with partial variables."""
    template = ChatPromptTemplate.from_messages(
        [
            (SystemMessage, "You are {name}, a {role} assistant."),
            (HumanMessage, "{question}"),
        ]
    )

    partial_template = template.partial(name="Alice", role="helpful")
    messages = partial_template.format_messages(question="What is Python?")

    assert len(messages) == 2
    assert messages[0].content == "You are Alice, a helpful assistant."
    assert messages[1].content == "What is Python?"