pyo3-testing: A crate to make testing pyo3 wrapped functions easy in rust

Pyo3-testing is designed to save the need to continually build and install your wrapped extension modules in order to run integration tests in python.

It provides a test attribute #[pyo3test] which allows you to shorten your tests to:

#[pyo3test]
#[pyo3import(py_adders: from adders import addone)]
fn test_pyo3test_simple_case() {
    let result: isize = addone!(1);
    assert_eq!(result, 2);
}

Without pyo3-testing this test can run to over 20 lines of code and randomly fail due to issues with python interpreter pre-initialisation.

It also provides a with_py_raises! macro modelled on pytest's with raises context manager to test for expected Exceptions:

# use pyo3_testing::{pyo3test, with_py_raises};
#[pyo3test]
#[allow(unused_macros)]
#[pyo3import(py_adders: from adders import addone)]
fn test_raises() {
    with_py_raises!(PyTypeError, { addone.call1(("4",)) });
}

For a walk-through guide to using the crate along with lots of other tips on developing rust extensions for python see: Combining rust & python - a worked example

Technical documentation for the crate is available at docs.rs

Supported pyo3 version(s)

As of v0.28.0 pyo3_testing version numbers will shadow pyo3's left-most non-zero major/minor version. This is to simplify things so that you and cargo can always find the right match.

pyo3 has recently made a series of breaking changes to the underlying functionality needed for this crate. Cargo should use the correct version of this crate to match the version of pyo3, but in case you run into issues compatibility is as follows:

• technically compatible but refused by cargo's treatment of 0.x sermver

Recognition

This crate wouldn't be possible or necessary without the amazing work done by pyo3

Feedback, ideas and contributions

... are very welcome via MusicalNinjas/pyo3-testing