The pytest framework makes it easy to write small tests, yet scales to support complex functional testing for applications and libraries.

An example of a simple test:

# content of test_sample.py
def func(x):
    return x + 1

def test_answer():
    assert func(3) == 5

To execute it:

$ py.test
======= test session starts ========
platform linux -- Python 3.4.3, pytest-2.8.5, py-1.4.31, pluggy-0.3.1    
collected 1 items

test_sample.py F

======= FAILURES ========
_______ test_answer ________

    def test_answer():
>       assert func(3) == 5
E       assert 4 == 5
E        +  where 4 = func(3)

test_sample.py:5: AssertionError
======= 1 failed in 0.12 seconds ========

Due to py.test's detailed assertion introspection, only plain assert statements are used. See getting-started for more examples.

• Detailed info on failing assert statements (no need to remember self.assert* names);
• Auto-discovery of test modules and functions;
• Modular fixtures for managing small or parametrized long-lived test resources;
• Can run unittest (or trial), nose test suites out of the box;
• Python2.6+, Python3.2+, PyPy-2.3, Jython-2.5 (untested);
• Rich plugin architecture, with over 150+ external plugins and thriving community;

For full documentation, including installation, tutorials and PDF documents, please see http://pytest.org.

Please use the GitHub issue tracker to submit bugs or request features.

Consult the Changelog page for fixes and enhancements of each version.

Copyright Holger Krekel and others, 2004-2016.

Distributed under the terms of the MIT license, pytest is free and open source software.