<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude" version="5.0" xml:id="sec-nixos-tests"> <title>NixOS Tests</title> <para>When you add some feature to NixOS, you should write a test for it. NixOS tests are kept in the directory <filename xlink:href="https://github.com/NixOS/nixpkgs/tree/master/nixos/tests">nixos/tests</filename>, and are executed (using Nix) by a testing framework that automatically starts one or more virtual machines containing the NixOS system(s) required for the test.</para> <xi:include href="writing-nixos-tests.xml" /> <xi:include href="running-nixos-tests.xml" /> </chapter>