nixosTests.scx: init (#401972)

For now, test only the useful schedulers, there's no need to test all of them.

Co-authored-by: Gliczy <[e-mail]>
Signed-off-by: John Titor <[e-mail]>

nixos/tests/all-tests.nix

···
   schleuder = handleTest ./schleuder.nix { };
   scion-freestanding-deployment = handleTest ./scion/freestanding-deployment { };
   scrutiny = runTest ./scrutiny.nix;
+  scx = runTest ./scx/default.nix;
   sddm = handleTest ./sddm.nix { };
   sdl3 = handleTest ./sdl3.nix { };
   seafile = handleTest ./seafile.nix { };

nixos/tests/scx/default.nix

···
+{ pkgs, ... }:
+
+{
+  name = "scx_full";
+  meta = {
+    inherit (pkgs.scx.full.meta) maintainers;
+  };
+
+  nodes.machine = {
+    boot.kernelPackages = pkgs.linuxPackages_latest;
+    services.scx.enable = true;
+
+    specialisation = {
+      bpfland.configuration.services.scx.scheduler = "scx_bpfland";
+      central.configuration.services.scx.scheduler = "scx_central";
+      lavd.configuration.services.scx.scheduler = "scx_lavd";
+      rlfifo.configuration.services.scx.scheduler = "scx_rlfifo";
+      rustland.configuration.services.scx.scheduler = "scx_rustland";
+      rusty.configuration.services.scx.scheduler = "scx_rusty";
+    };
+  };
+
+  testScript = ''
+    specialisation = [
+      "bpfland",
+      "central",
+      "lavd",
+      "rlfifo",
+      "rustland",
+      "rusty"
+    ]
+
+    def activate_specialisation(name: str):
+      machine.succeed(f"/run/booted-system/specialisation/{name}/bin/switch-to-configuration test >&2")
+
+    for sched in specialisation:
+      with subtest(f"{sched}"):
+        activate_specialisation(sched)
+        machine.succeed("systemctl restart scx.service")
+        machine.succeed(f"ps -U root -u root u | grep scx_{sched}")
+  '';
+}

pkgs/os-specific/linux/scx/scx_full.nix

···
   stdenv,
   scx-common,
   scx,
+  nixosTests,
 }:
 scx.cscheds.overrideAttrs (oldAttrs: {
   pname = "scx_full";
···
     + ''
       cp ${scx.rustscheds}/bin/* ${placeholder "bin"}/bin/
     '';
+
+  passthru.tests.basic = nixosTests.scx;
 
   passthru.updateScript.command = ./update.sh;