pytest-infuse

Rust-powered pytest collection. Run your tests the same way you always do — just faster.

The package is pytest-infuse; the binary it installs is called infuse.

Beta / work in progress — pytest-infuse is still in early stages. It works for typical pytest layouts, but expect rough edges and changes as it evolves.

What it does

Pytest’s normal lifecycle is: discover which files might be tests, collect them (import modules, find test functions and classes), then run the tests. The discovery and collection steps are done in Python and can be slow on large trees.

Infuse is a small Rust binary that does discovery and test-name extraction very quickly. The conftest.py that infuse init creates plugs into pytest’s hooks: it runs infuse once at the start, then hijacks which paths pytest collects (pytest_ignore_collect) and which items are kept and in what order (pytest_collection_modifyitems). Pytest still imports and runs your tests — it just no longer decides which files to look at or in what order; infuse does. Same tests, same commands, faster collection.

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How to use (that’s it)

1. Have infuse on your PATH, or set INFUSE_BIN to the path of the infuse binary.
2. In your Python project directory, run:

   infuse init

   When prompted, answer y to generate conftest.py.
3. Run pytest exactly as you already do:

   pytest
   # or
   uv run pytest
   # or
   pytest -v
   pytest tests/
   # etc.

No other workflow changes. No extra flags. You just get faster collection.

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Installation

Build the binary and make it available to your projects:

git clone https://github.com/narven/pytest-infuse.git
cd pytest-infuse
cargo build --release

Then either:

• Put target/release/infuse on your PATH, or
• Set INFUSE_BIN to the full path to infuse when running pytest (e.g. in your shell or env).

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For more information

infuse init — Run in a project directory. If there’s no conftest.py, it asks whether to create one. That conftest wires pytest to infuse so collection is driven by the Rust binary.

infuse collect — For special cases only (e.g. scripting or debugging). Discovers test files under a directory and prints a JSON manifest of test node IDs. You don’t need to run this yourself when using infuse with pytest; the conftest does it for you.

infuse collect .                              # current dir, default pattern test_*.py
infuse collect /path/to/project --pattern "test_*.py"

If the infuse binary isn’t found or fails, pytest falls back to normal collection — your runs still work, just without the speedup.

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License

MIT. See LICENSE.