How to install py.test?

Question 1

In general, installing a package in Python is pretty simple if you use pip which is already installed if you're using Python 2 >=2.7.9 or Python 3 >=3.4.

In order to install pytest:

Python 2: $ pip install pytest

Python 3: $ pip3 install pytest

However, it is a good practice to isolate Python environments by creating a virtual environment. In order to install pytest in an isolated virtual environment:

Python 2

$ pip install -U virtualenv
$ python -m virtualenv venv
$ source venv/bin/activate # in Windows -> $ venv\Scripts\activate.bat
$ pip install pytest

Python 3

$ pip3 install -U virtualenv
$ python3 -m virtualenv venv
$ source venv/bin/activate # in Windows -> $ venv\Scripts\activate.bat
$ pip install pytest

Python 3.6+

$ python3 -m venv venv
$ source venv/bin/activate # in Windows -> $ venv\Scripts\activate.bat
$ pip install pytest

Question 2

Maybe you're looking for something like pip.

For example, if you want to install Cherrypy you must to run

    pip install cherrypy

or if you're using python3, and depending of your distro, the command is

    pip3 install cherrypy

If you're downloading a package from source, then you must to uncompress it and normally, depending the package, you must to run (as administrator or root)

    python setup.py install