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Setting up NixOS Integration Tests

To run NixOS integration tests, you basically just need Nix and, for the best experience, KVM support.

  • Linux

    The test driver can run virtual machines (qemu) and containers (systemd-nspawn). For good VM performance, run a bare-metal instance of Linux.

  • macOS

    The test driver also runs on macOS. Only VMs are supported, not containers.

    See macOS setup

  • Nix

    Use the multi-user installation for best experience.

    See Nix install & check

  • KVM

    Hardware-accelerated virtualisation makes VM tests fast.

    See KVM check

Installation and setup check

Nix

The tests are all built and run with Nix. To install Nix, run the following command (see also Nix installer page):

sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install) --daemon

Test your Nix installation like this:

$ nix --experimental-features "nix-command flakes" run nixpkgs#hello
Hello, world!

If this works, you are ready to go: Continue writing your first minimal NixOS test here

Linux KVM

The important bit is that KVM is enabled, which enables hardware-accelerated virtualization. The tests also run without KVM but will be very slow in that case.

Check your KVM configuration:

  1. Running lsmod should show that the kvm modules (with hardware platform specific kvm_* variants) are loaded: 
    $ lsmod | grep kvm
kvm_amd               245760  0
ccp                   212992  1 kvm_amd
kvm                  1425408  1 kvm_amd
irqbypass              16384  1 kvm
  2. Check that you and the Nix build users have write-access to /dev/kvm: 
    $ ls -l /dev/kvm
crw-rw-rw- 1 root kvm 10, 232 Apr  6 19:18 /dev/kvm
    In this configuration, anyone has write-access to /dev/kvm, which is the simplest configuration method.

macOS setup

NixOS integration tests can run on macOS (Apple Silicon) by using a Linux builder or the apple-virt virtualization framework. For more details, see the Nixcademy NixOS test driver guide for macOS.