pyneedy 1.0.0

A minimal library for writing tests with optional dependencies.

Needy

A minimal library for writing tests with optional dependencies.

Installation

Python 3.11+ is required.

pip install pyneedy

Quick Start

Define "probes" for the optional dependencies you want to use, e.g. JAX.

class check:
    @staticmethod
    def jax() -> None:
        # A probe just tries to import the optional dependency.
        import jax as jax

Then wrap imports related to the optional dependency in a needs.modules(...) scope like this:

from needy import needs

from pytest import mark

with needs.modules(check.jax):
    import jax.numpy as jnp

@mark.parametrize(
    ["array", "expected_sum"],
    [
        (
            array := jnp.array([1.0, 2.0]),
            expected_sum := 3.0
        ),
        (
            array := jnp.array([]),
            expected_sum := 0.0
        )
    ]
)
def test_that_a_sum_is_computed(array, expected_sum) -> None:
    assert array.sum() == expected_sum

If jax is installed, the imports inside the with block resolve normally. If it isn't, every missing import inside the block is replaced with a proxy, and only the first real use of the missing modules will raise an error.

See the docs for more.

Development

Prerequisites

• Python >= 3.11
• uv (recommended) or pip
• just (optional, for convenience)

Getting Started

1. Clone the repository:

   git clone https://gitlab.com/pytooling/needy.git
   cd needy
   

2. Create a virtual environment and install dependencies:

   uv sync
   

3. Install pre-commit hooks:

   uv run pre-commit install
   

Running Checks

just check

Or manually:

uv run ruff check --fix && uv run ruff format && uv run pyright && uv run pytest

License

This project is licensed under the MIT License. See LICENSE for details.