langchain/tests/unit_tests/prompts/test_prompt.py

"""Test functionality related to prompts."""
import pytest

from langchain.prompts.prompt import PromptTemplate


def test_prompt_valid() -> None:
    """Test prompts can be constructed."""
    template = "This is a {foo} test."
    input_variables = ["foo"]
    prompt = PromptTemplate(input_variables=input_variables, template=template)
    assert prompt.template == template
    assert prompt.input_variables == input_variables


def test_prompt_missing_input_variables() -> None:
    """Test error is raised when input variables are not provided."""
    template = "This is a {foo} test."
    input_variables: list = []
    with pytest.raises(ValueError):
        PromptTemplate(input_variables=input_variables, template=template)


def test_prompt_extra_input_variables() -> None:
    """Test error is raised when there are too many input variables."""
    template = "This is a {foo} test."
    input_variables = ["foo", "bar"]
    with pytest.raises(ValueError):
        PromptTemplate(input_variables=input_variables, template=template)


def test_prompt_wrong_input_variables() -> None:
    """Test error is raised when name of input variable is wrong."""
    template = "This is a {foo} test."
    input_variables = ["bar"]
    with pytest.raises(ValueError):
        PromptTemplate(input_variables=input_variables, template=template)


def test_prompt_from_examples_valid() -> None:
    """Test prompt can be successfully constructed from examples."""
    template = """Test Prompt:

Question: who are you?
Answer: foo

Question: what are you?
Answer: bar

Question: {question}
Answer:"""
    input_variables = ["question"]
    example_separator = "\n\n"
    prefix = """Test Prompt:"""
    suffix = """Question: {question}\nAnswer:"""
    examples = [
        """Question: who are you?\nAnswer: foo""",
        """Question: what are you?\nAnswer: bar""",
    ]
    prompt_from_examples = PromptTemplate.from_examples(
        examples,
        suffix,
        input_variables,
        example_separator=example_separator,
        prefix=prefix,
    )
    prompt_from_template = PromptTemplate(
        input_variables=input_variables, template=template
    )
    assert prompt_from_examples.template == prompt_from_template.template
    assert prompt_from_examples.input_variables == prompt_from_template.input_variables


def test_prompt_invalid_template_format() -> None:
    """Test initializing a prompt with invalid template format."""
    template = "This is a {foo} test."
    input_variables = ["foo"]
    with pytest.raises(ValueError):
        PromptTemplate(
            input_variables=input_variables, template=template, template_format="bar"
        )


def test_prompt_from_file() -> None:
    """Test prompt can be successfully constructed from a file."""
    template_file = "tests/unit_tests/data/prompt_file.txt"
    input_variables = ["question"]
    prompt = PromptTemplate.from_file(template_file, input_variables)
    assert prompt.template == "Question: {question}\nAnswer:"