Make sure you quit the Django development server. You just need to press Ctrl + C in the Terminal or Command Prompt window in which it is running.
Now, we will install many additional packages to be able to easily run tests and measure their code coverage. Make sure you have activated the virtual environment that we created in the previous chapter, named Tornado01. After you activate the virtual environment, it is time to run many commands that will be the same for macOS, Linux, and Windows.
Now, we will edit the existing requirements.txt file to specify the additional packages that our application requires to be installed on any supported platform. This way, it will be extremely easy to repeat the installation of the specified packages with their versions in any new virtual environment.
Use your favorite editor to edit the existing text file...
