nixpkgs/nixos/doc/manual/development/running-nixos-tests-interactively.xml
Andreas Rammhold 20893b3a70
nixos/tests: expose both the interactive and non-interactive driver
For a lot of the work the non-interactive drivers are enough and it is
probably a good idea to keep it accessible for debugging without
touching the Nix expression.
2020-10-19 17:39:48 +02:00

50 lines
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XML

<section 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-running-nixos-tests-interactively">
<title>Running Tests interactively</title>
<para>
The test itself can be run interactively. This is particularly useful when
developing or debugging a test:
<screen>
<prompt>$ </prompt>nix-build nixos/tests/login.nix -A driverInteractive
<prompt>$ </prompt>./result/bin/nixos-test-driver
starting VDE switch for network 1
<prompt>&gt;</prompt>
</screen>
You can then take any Python statement, e.g.
<screen>
<prompt>&gt;</prompt> start_all()
<prompt>&gt;</prompt> test_script()
<prompt>&gt;</prompt> machine.succeed("touch /tmp/foo")
<prompt>&gt;</prompt> print(machine.succeed("pwd")) # Show stdout of command
</screen>
The function <command>test_script</command> executes the entire test script
and drops you back into the test driver command line upon its completion.
This allows you to inspect the state of the VMs after the test (e.g. to debug
the test script).
</para>
<para>
To just start and experiment with the VMs, run:
<screen>
<prompt>$ </prompt>nix-build nixos/tests/login.nix -A driverInteractive
<prompt>$ </prompt>./result/bin/nixos-run-vms
</screen>
The script <command>nixos-run-vms</command> starts the virtual machines
defined by test.
</para>
<para>
You can re-use the VM states coming from a previous run
by setting the <command>--keep-vm-state</command> flag.
<screen>
<prompt>$ </prompt>./result/bin/nixos-run-vms --keep-vm-state
</screen>
The machine state is stored in the
<filename>$TMPDIR/vm-state-</filename><varname>machinename</varname> directory.
</para>
</section>