pyrox.dev
1# Running Tests interactively {#sec-running-nixos-tests-interactively}
2
3The test itself can be run interactively. This is particularly useful
4when developing or debugging a test:
5
6```ShellSession
7$ nix-build . -A nixosTests.login.driverInteractive
8$ ./result/bin/nixos-test-driver
9[...]
10>>>
11```
12
13You can then take any Python statement, e.g.
14
15```py
16>>> start_all()
17>>> test_script()
18>>> machine.succeed("touch /tmp/foo")
19>>> print(machine.succeed("pwd")) # Show stdout of command
20```
21
22The function `test_script` executes the entire test script and drops you
23back into the test driver command line upon its completion. This allows
24you to inspect the state of the VMs after the test (e.g. to debug the
25test script).
26
27## Shell access in interactive mode {#sec-nixos-test-shell-access}
28
29The function `<yourmachine>.shell_interact()` grants access to a shell running
30inside a virtual machine. To use it, replace `<yourmachine>` with the name of a
31virtual machine defined in the test, for example: `machine.shell_interact()`.
32Keep in mind that this shell may not display everything correctly as it is
33running within an interactive Python REPL, and logging output from the virtual
34machine may overwrite input and output from the guest shell:
35
36```py
37>>> machine.shell_interact()
38machine: Terminal is ready (there is no initial prompt):
39$ hostname
40machine
41```
42
43As an alternative, you can proxy the guest shell to a local TCP server by first
44starting a TCP server in a terminal using the command:
45
46```ShellSession
47$ socat 'READLINE,PROMPT=$ ' tcp-listen:4444,reuseaddr`
48```
49
50In the terminal where the test driver is running, connect to this server by
51using:
52
53```py
54>>> machine.shell_interact("tcp:127.0.0.1:4444")
55```
56
57Once the connection is established, you can enter commands in the socat terminal
58where socat is running.
59
60## Reuse VM state {#sec-nixos-test-reuse-vm-state}
61
62You can re-use the VM states coming from a previous run by setting the
63`--keep-vm-state` flag.
64
65```ShellSession
66$ ./result/bin/nixos-test-driver --keep-vm-state
67```
68
69The machine state is stored in the `$TMPDIR/vm-state-machinename`
70directory.
71
72## Interactive-only test configuration {#sec-nixos-test-interactive-configuration}
73
74The `.driverInteractive` attribute combines the regular test configuration with
75definitions from the [`interactive` submodule](#test-opt-interactive). This gives you
76a more usable, graphical, but slightly different configuration.
77
78You can add your own interactive-only test configuration by adding extra
79configuration to the [`interactive` submodule](#test-opt-interactive).
80
81To interactively run only the regular configuration, build the `<test>.driver` attribute
82instead, and call it with the flag `result/bin/nixos-test-driver --interactive`.