https://github.com/boxed/hammett

Fast python test runner, compatible with a subset of pytest
https://github.com/boxed/hammett

pytest python testing testing-tools

Last synced: 3 days ago
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Fast python test runner, compatible with a subset of pytest

• Host: GitHub
• URL: https://github.com/boxed/hammett
• Owner: boxed
• License: bsd-3-clause
• Created: 2020-03-15T15:13:14.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2024-09-23T10:59:33.000Z (4 months ago)
• Last Synced: 2025-01-04T03:08:13.905Z (10 days ago)
• Topics: pytest, python, testing, testing-tools
• Language: Python
• Homepage:
• Size: 327 KB
• Stars: 91
• Watchers: 3
• Forks: 7
• Open Issues: 7
• Metadata Files:
  • Readme: README.rst
  • Changelog: HISTORY.rst
  • License: LICENSE
  • Authors: AUTHORS.rst

Awesome Lists containing this project

• awesome-python-testing - hammett - Fast python test runner, compatible with a subset of pytest. (Testing Frameworks)

README

        
hammett

=======

.. image:: https://travis-ci.org/boxed/hammett.svg?branch=master

    :target: https://travis-ci.org/boxed/hammett

.. image:: https://codecov.io/gh/boxed/hammett/branch/master/graph/badge.svg

  :target: https://codecov.io/gh/boxed/hammett

Hammett is a fast python test runner that aims to be compatible with the parts

of pytest most people use (unless that conflicts with the goal of being fast).

It also adds some features that can dramatically improve your testing experience

if you adapt more fully to hammett.

How much faster is hammett?

---------------------------

This will depend on how fast your test suite is.

Hammett isn't magic, it's just a runner made by someone who cares about

performance a lot. It aims to have minimal startup overhead and minimal

overhead for each test. I have written some benchmarks for measuring this

overhead which you can find at https://github.com/boxed/test-benchmarks (TL;DR

if your test suite is < 1s in pytest you will see VAST improvements, if it's

minutes or hours, not so much).

A real world example is running the test suite of tri.declarative:

- pytest: ~860 ms

- hammett: ~160 ms

Or iommi:

- pytest: ~10 s

- hammett: ~8 s

But even if your test suite is big and slow you can still get some big

improvements out of hammett if you often run just one file or one test:

In iommi, running `-k test_render_attrs_none`

- pytest: ~1.3 s

- hammett: ~0.6 s

All of this is from a full and clean run. Hammett has features to avoid that!

Tests locked to a module

------------------------

In hammett you can optionally name your test files `module__tests.py` (that's

two `_`). This tells hammett that if you change `module` only the tests in

`module__tests.py` needs to be run. You can place those files either in the

tests directory or right next to the module you're testing.

Run just relevant tests

------------------------

Hammett keeps track of what modules and what tests have changed and runs only

the tests it needs to. Assuming you lock your tests to a module like above.

If hammett gets confused you can delete the `.hammett-db` file and it will

start from scratch.

Pytest features that work in hammett

------------------------------------

- `pytest.mark`

- parametrized tests

- fixtures

- `with pytest.raises`

Some plugins work, but you have to specify to load them in setup.cfg:

.. code:: ini

    [hammett]

    plugins=

        pytest_django

Usage

------

First install: :code:`pip install hammett`

Then run hammett: :code:`python -m hammett`

Hopefully it will run your entire test suite!

Hammett works with some pytest plugins, most notably pytest-django, at least

for some projects. You need to specify what plugins hammett loads manually

in setup.cfg though.

Keeping pytest compatibility

----------------------------

If you want to use the hammett specific feature of `module__tests.py`-style

test files, you can still keep compatibility with pytest by specifying the

module of your project and the tests file pattern, like this:

.. code::

    testpaths=

        tests

        my_project

    python_files=

        *__tests.py

Also keep importing pytest instead of hammett obviously.

License

-------

BSD