Modern Python Projects Transcripts
Chapter: CI
Lecture: tox - automate Python tasks on your computer
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One way to automate those tasks is to use a tool like Tox. Tox is a Python automation tool.
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I have seen it most commonly used by developers who create Python packages.
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That's because they need to test if they're package works with different versions of Python.
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Let's say you need to make sure that your Python package works with Python 3.4 3.6, 6,7,8,9 and 10 That's seven versions of Python.
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If you want to manually tested, it will take you ages. You will need to create seven different virtual environments,
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one for each different version of Python, then go inside each of them and run test. But you can instead automate all of that with Tox.
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You will first have to write a configuration file called tox.ini and then in
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that file, you specify one version of Python you want to use and what commands you want to run. The most common one is to run py test to make
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sure that all tests are passing under each version of Python. But you can also run any additional command.
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For example, you can run some static analysis tools like bandit to make sure that none of the Python versions has any security vulnerabilities.
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Once you write this file, you just run Tox, command, and you check if there any errors, here We have a very simple example,
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but Tox is actually quite powerful. One of the really cool feature is that you can specify a test matrix.
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So you can say that you want to test different versions of Python, but also for each version of Python,
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you want to use different version of a specific dependency. For example, here we say that we want to use Python 3.6,7 and 8,
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and then for each of those Python versions, we want to use Django 2.2 and Django 3. And then for each of those Django versions,
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we want to use SQlite and mySQL. As a database engine. This one line of configuration creates 12 different testing environments.
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The first one will have Python 3.6, Django 2.2 and SQLite. The second one will have Python 3.6 and Django 2.2
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as well, But this time we will use mySQL and so on Once we have all that prepared Tox will run tests inside each of them, trying
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to re create and maintain This kind of set up by hand would take you a lot of time. And to be honest, it would be boring as hell.