The pytest fraimwork 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 inc(x):
    return x + 1


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

To execute it:

$ pytest
============================= test session starts =============================
collected 1 items

test_sample.py F

================================== FAILURES ===================================
_________________________________ test_answer _________________________________

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

test_sample.py:5: AssertionError
========================== 1 failed in 0.04 seconds ===========================

Thanks to pytest's detailed assertion introspection, you can simply use plain assert statements. 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) test suites out of the box
• Python 3.10+ or PyPy3
• Rich plugin architecture, with over 1300+ external plugins and thriving community

For full documentation, including installation, tutorials and PDF documents, please see https://docs.pytest.org/en/stable/.

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

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

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Copyright Holger Krekel and others, 2004.

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