oxytest 1.0.0

A 100% pytest-compatible test runner written in Python + Rust, optimized for speed

Oxytest

A 100% pytest-compatible test runner written in Python + Rust via PyO3 and Maturin. Designed for speed in large codebases.

Why Oxytest?

pytest is great, but it can be slow for large projects. Oxytest is a drop-in replacement that is 10-100x faster at test discovery and supports parallel execution out of the box.

Feature	pytest	oxytest
Discovery	Import-based (slow)	AST-based (fast)
Parallel	Requires pytest-xdist	Built-in (Rayon)
Language	Python	Python + Rust
Assert rewriting	Built-in	Built-in (comparison diffs)
Plugin system	Built-in	Built-in (pluggy)
Drop-in compatible	—	100%

Quick Start

# Install
pip install oxytest

# Run tests (no changes needed!)
oxytest

# Use as pytest replacement
python -c "import oxytest as pytest; pytest.main()"

Usage

# Run all tests in current directory
oxytest

# Run with parallel execution (auto-detect CPU count)
oxytest -n auto

# Verbose output
oxytest -v

# Stop on first failure
oxytest -x

# Filter by keyword
oxytest -k "user or math"

# Show local variables on failure
oxytest --showlocals

# Trace fixture setup/teardown
oxytest --setup-show

# Run only previously failed tests
oxytest --lf

# Show slowest tests
oxytest --durations 5

# Full summary
oxytest -rA

# Migrate imports from pytest to oxytest
oxytest migrate src/ --dry-run

Python API

import oxytest as pytest

# All standard pytest API is available
pytest.main(["-v", "tests/"])

assert 0.1 + 0.2 == pytest.approx(0.3)

with pytest.raises(ValueError):
    int("not a number")

@pytest.fixture
def data():
    return {"key": "value"}

@pytest.mark.parametrize("x,expected", [(1, 2), (3, 6)])
def test_double(x, expected):
    assert x * 2 == expected

# Plugin API
from oxytest import hookimpl
@hookimpl
def pytest_addoption(parser):
    parser.addoption("--my-flag", action="store_true")

Benchmarks

Reproduce with the built-in generator for a fair comparison (sequential only, no -n flag):

# Generate 500 files with 10 tests each, 1ms sleep per test
python benchmarks/generate.py --num-files 500 --tests-per-file 10 --sleep-ms 1

# Sequential comparison (fair: no -n flag for either)
time python -m oxytest benchmark_tests/ --tb=no -q
time python -m pytest benchmark_tests/ --tb=no -q

# Parallel comparison
time python -m oxytest benchmark_tests/ --tb=no -q -n auto
time python -m pytest benchmark_tests/ --tb=no -q -n auto   # requires pytest-xdist

Results for 5000 tests with 1ms sleep each:

Mode	pytest	oxytest	Speedup
Sequential	11.45s	5.85s	2.0x
Parallel (8 workers)	—	0.57s	20x

Discovery alone (500 files, no sleep):

Tool	Time
pytest	~2.5s
oxytest	~0.05s

Documentation

• English
• Español

Development

# Clone
git clone https://github.com/rroblf01/oxytest
cd oxytest

# Install dependencies
uv sync

# Build the Rust extension
uv pip install -e .

# Run tests
oxytest tests/

License

MIT