how to install pytest for python3 on mac

In my last article, I spoke at some length about the terminology used around automated testing, and made some arguments about why you should be using automated testing.

Pytest For Python3 On How To Actually Get

In this article, Im going to be getting on the tools to show you how to actually get started with unit testing.

Im going to cover enough for you to write your first unit test with Pytest, and then Im going to show you how to use parametization which is one of my favorite tools to use to write useful unit tests.

Pytest For Python3 On Code And Running

If you havent worked with Pytest before, youre going to get the most out of it by actually working through the tutorial by writing out the code and running it on your computer.

Photo by Chris Ried on Unsplash Installing Pytest The first step of adding unit testing is adding your unit test framework.

In Python, I tend to use Pytest instead of the unittest module thats included in Pythons standard library - as it provides some useful out-of-the-box features (like parametization), and I find the way that it structures tests to be more intuitive.

Setting up a virtual environment For this tutorial, we need to work with a virtual environment.

If you already know how to set up and activate a virtual environment, skip this section.

Using a virtual environment is an easy way to separate the projects that you are working on, and the potentially clashing pip packages that are required for them.

Creating the environment If you havent already, create a folder for your project Go into your terminal, and navigate to the folder Create a virtual environment in a folder called env by running python3 -m venv env in your terminal A note about Debian and Ubuntu The venv module isnt installed by default in Debian or Ubuntu.

Youll need to install it by runnning: sudo apt install python3-venv.

Activating the environment This is one thing that differs a little bit depending on your OS and shell.

On LinuxUnixMacOS with sh or compatible: run source envbinactivate in your shell On Windows with cmd: run source envscriptsactivate.bat in your terminal On Windows with Powershell: run source envscriptsactivate.ps1 in Powershell A note about Powershell and permissions One way that Microsoft increased the safety of Powershell over cmd is by limiting what scripts you are able to run.

You can find Microsofts documentation on what this does here.

You need to set it to RemoteSigned to run the virtual environment.

Do this by starting Powershell in Administrator Mode (by right clicking it in the Start menu, and choosing Run as Administrator) and then running the command Set-ExecutionPolicy RemoteSigned.

Verify Pytest is installed by running the command python -m pytest in your shell.

You should see some output like the following: Were running Pytest by python -m pytest intentionally here.

Alternatively, you run pytest - but it that way requires some additional work.

The basic reason is that just calling pytest changes the paths that Python searches for imports - see here.

Basically - Im taking this route to make it as easy as possible to write some useful tests.

Writing a test Pytest, by default, looks for tests recursively in the folder you start it in, by looking for files called test.py or test.py ( see Pytest Test Discovery ).

How To Install Pytest For Python3 On Mac