kbd: add simple tests for binaries

[davidak]

Issue description

When reviewing PRs to update kbd, i have to run binaries manually to see if they start. We should automate that!

As first step we can check --version on all in /bin. Not sure how basic functionality should be tested. There are already NixOS tests.

[nix-shell:~/.cache/nixpkgs-review/pr-256569-1]$ ll /nix/store/mbcdwg8fm1plc2jggl8r4a9kybcdgln3-kbd-2.6.3/bin/
total 724
-r-xr-xr-x 1 root root 17104 Jan  1  1970 chvt
-r-xr-xr-x 1 root root 21992 Jan  1  1970 clrunimap
-r-xr-xr-x 1 root root 16832 Jan  1  1970 deallocvt
-r-xr-xr-x 1 root root 17816 Jan  1  1970 dumpkeys
-r-xr-xr-x 1 root root 16784 Jan  1  1970 fgconsole
-r-xr-xr-x 1 root root 16784 Jan  1  1970 getkeycodes
-r-xr-xr-x 1 root root 22384 Jan  1  1970 getunimap
-r-xr-xr-x 1 root root 16960 Jan  1  1970 kbdinfo
-r-xr-xr-x 1 root root 17120 Jan  1  1970 kbd_mode
-r-xr-xr-x 1 root root 17184 Jan  1  1970 kbdrate
-r-xr-xr-x 1 root root 26264 Jan  1  1970 loadkeys
-r-xr-xr-x 1 root root 40240 Jan  1  1970 loadunimap
-r-xr-xr-x 1 root root 31112 Jan  1  1970 mapscrn
-r-xr-xr-x 1 root root 26728 Jan  1  1970 openvt
-r-xr-xr-x 1 root root 15776 Jan  1  1970 outpsfheader
lrwxrwxrwx 1 root root     9 Jan  1  1970 psfaddtable -> psfxtable
lrwxrwxrwx 1 root root     9 Jan  1  1970 psfgettable -> psfxtable
lrwxrwxrwx 1 root root     9 Jan  1  1970 psfstriptable -> psfxtable
-r-xr-xr-x 1 root root 31024 Jan  1  1970 psfxtable
-r-xr-xr-x 1 root root 21400 Jan  1  1970 resizecons
-r-xr-xr-x 1 root root 16624 Jan  1  1970 screendump
-r-xr-xr-x 1 root root 53760 Jan  1  1970 setfont
-r-xr-xr-x 1 root root 16864 Jan  1  1970 setkeycodes
-r-xr-xr-x 1 root root 16680 Jan  1  1970 setleds
-r-xr-xr-x 1 root root 16648 Jan  1  1970 setlogcons
-r-xr-xr-x 1 root root 17040 Jan  1  1970 setmetamode
-r-xr-xr-x 1 root root 16608 Jan  1  1970 setpalette
-r-xr-xr-x 1 root root 16608 Jan  1  1970 setvesablank
-r-xr-xr-x 1 root root 17216 Jan  1  1970 setvtrgb
-r-xr-xr-x 1 root root 26888 Jan  1  1970 showconsolefont
-r-xr-xr-x 1 root root 21432 Jan  1  1970 showkey
-r-xr-xr-x 1 root root 16456 Jan  1  1970 spawn_console
-r-xr-xr-x 1 root root 16456 Jan  1  1970 spawn_login
-r-xr-xr-x 1 root root  2544 Jan  1  1970 unicode_start
-r-xr-xr-x 1 root root   470 Jan  1  1970 unicode_stop

Reference:

https://kbd-project.org/docs/howto-linux-keyboard-and-console/kbd.html https://kbd-project.org/docs/howto-linux-keyboard-and-console/kbd-1.html https://kbd-project.org/manpages/index.html

[tomodachi94]

As first step we can check --version on all in /bin. Not sure how basic functionality should be tested. There are already NixOS tests.

testers.testVersion can help with that.