#pytest: helps you write better programs
a mature full-featured Python testing tool
runs on Posix/Windows, Python 2.6-3.5, #PyPy and (possibly still) Jython-2.5.1
free and open source software, distributed under the terms of the MIT license
well tested with more than a thousand tests against itself
strict backward compatibility policy for safe pytest upgrades
comprehensive online and PDF documentation
many third party plugins and builtin helpers,
used in many small and large projects and organisations
comes with many tested examples
http://docs.pytest.org/en/latest/
https://www.infoworld.com/article/3230202/python/6-essential-libraries-for-every-python-developer.html
6 essential libraries for every Python developer
Whether you're compiling Python for speed, building native UIs for Python desktop apps, or refining existing Python code, these Python projects have you covered
Python has seen wide adoption across industries and disciplines by dint of being easy to work with. But it has also been aided by a wealth of third-party projects—libraries, add-ons, and complementary development efforts—that extend the language to an ever widening range of use cases.
#PyPy
#CFFI(C Foreign Function Interface library)
#PyInstaller
#PBR(Python Build Reasonableness)
#WxPython
#Mypy