nixos/swapspace: add tests

Signed-off-by: phanirithvij <phanirithvij2000@gmail.com>

nixos/tests/all-tests.nix

@@ -971,6 +971,7 @@ in {
   swap-file-btrfs = handleTest ./swap-file-btrfs.nix {};
   swap-partition = handleTest ./swap-partition.nix {};
   swap-random-encryption = handleTest ./swap-random-encryption.nix {};
+  swapspace = handleTestOn ["aarch64-linux" "x86_64-linux"] ./swapspace.nix {};
   sway = handleTest ./sway.nix {};
   swayfx = handleTest ./swayfx.nix {};
   switchTest = handleTest ./switch-test.nix { ng = false; };

nixos/tests/swapspace.nix

@@ -0,0 +1,69 @@
+import ./make-test-python.nix (
+  { pkgs, lib, ... }:
+
+  {
+    name = "swapspace";
+
+    meta = with pkgs.lib.maintainers; {
+      maintainers = [
+        Luflosi
+        phanirithvij
+      ];
+    };
+
+    nodes.machine = {
+      virtualisation.memorySize = 512;
+
+      services.swapspace = {
+        enable = true;
+        extraArgs = [ "-v" ];
+        settings = {
+          # test outside /var/lib/swapspace
+          swappath = "/swamp";
+          cooldown = 1;
+        };
+      };
+
+      swapDevices = lib.mkOverride 0 [
+        {
+          size = 127;
+          device = "/root/swapfile";
+        }
+      ];
+      boot.kernel.sysctl."vm.swappiness" = 60;
+    };
+
+    testScript = ''
+      machine.wait_for_unit("multi-user.target")
+      machine.wait_for_unit("swapspace.service")
+      machine.wait_for_unit("root-swapfile.swap")
+
+      swamp = False
+      with subtest("swapspace works"):
+        machine.execute("mkdir /root/memfs")
+        machine.execute("mount -o size=2G -t tmpfs none /root/memfs")
+        i = 0
+        while i < 14:
+          print(machine.succeed("free -h"))
+          out = machine.succeed("sh -c 'swapon --show --noheadings --raw --bytes | grep /root/swapfile'")
+          row = out.split(' ')
+          # leave 1MB free to not get killed by oom
+          freebytes=int(row[2]) - int(row[3]) - 1*1024*1024
+          machine.succeed(f"dd if=/dev/random of=/root/memfs/{i} bs={freebytes} count=1")
+          machine.sleep(1)
+          out = machine.succeed("swapon --show")
+          print(out)
+          swamp = "/swamp" in out
+          if not swamp:
+            i += 1
+          else:
+            print("*"*10, "SWAPED", "*"*10)
+            machine.succeed("rm -f /root/memfs/*")
+            break
+
+      print(machine.succeed("swapspace -e -s /swamp"))
+      assert "/swamp" not in machine.execute("swapon --show")
+      assert swamp
+    '';
+  }
+)

pkgs/tools/admin/swapspace/default.nix

@@ -1,4 +1,14 @@
-{ lib, stdenv, fetchFromGitHub, autoreconfHook, installShellFiles, util-linux, binlore, swapspace }:
+{
+  lib,
+  stdenv,
+  fetchFromGitHub,
+  autoreconfHook,
+  installShellFiles,
+  util-linux,
+  binlore,
+  swapspace,
+  nixosTests,
+}:
 
 stdenv.mkDerivation rec {
   pname = "swapspace";
@@ -40,6 +50,9 @@ stdenv.mkDerivation rec {
   passthru.binlore.out = binlore.synthesize swapspace ''
     execer cannot bin/swapspace
   '';
+  passthru.tests = {
+    inherit (nixosTests) swapspace;
+  };
 
   meta = with lib; {
     description = "Dynamic swap manager for Linux";