nixos/amd.sev: add test

nixos/tests/all-tests.nix

···
   allTerminfo = handleTest ./all-terminfo.nix {};
   alps = handleTest ./alps.nix {};
   amazon-init-shell = handleTest ./amazon-init-shell.nix {};
+  amd-sev = runTest ./amd-sev.nix;
   anbox = runTest ./anbox.nix;
   anuko-time-tracker = handleTest ./anuko-time-tracker.nix {};
   apcupsd = handleTest ./apcupsd.nix {};

nixos/tests/amd-sev.nix

···
+{ lib, ... }: {
+  name = "amd-sev";
+  meta = {
+    maintainers = with lib.maintainers; [ trundle veehaitch ];
+  };
+
+  nodes.machine = { lib, ... }: {
+    hardware.cpu.amd.sev.enable = true;
+    hardware.cpu.amd.sevGuest.enable = true;
+
+    specialisation.sevCustomUserGroup.configuration = {
+      users.groups.sevtest = { };
+
+      hardware.cpu.amd.sev = {
+        enable = true;
+        group = "root";
+        mode = "0600";
+      };
+      hardware.cpu.amd.sevGuest = {
+        enable = true;
+        group = "sevtest";
+      };
+    };
+  };
+
+  testScript = { nodes, ... }:
+    let
+      specialisations = "${nodes.machine.system.build.toplevel}/specialisation";
+    in
+    ''
+      machine.wait_for_unit("multi-user.target")
+
+      with subtest("Check default settings"):
+        out = machine.succeed("cat /etc/udev/rules.d/99-local.rules")
+        assert 'KERNEL=="sev", OWNER="root", GROUP="sev", MODE="0660"' in out
+        assert 'KERNEL=="sev-guest", OWNER="root", GROUP="sev-guest", MODE="0660"' in out
+
+        out = machine.succeed("cat /etc/group")
+        assert "sev:" in out
+        assert "sev-guest:" in out
+        assert "sevtest:" not in out
+
+      with subtest("Activate configuration with custom user/group"):
+        machine.succeed('${specialisations}/sevCustomUserGroup/bin/switch-to-configuration test')
+
+      with subtest("Check custom user and group"):
+        out = machine.succeed("cat /etc/udev/rules.d/99-local.rules")
+        assert 'KERNEL=="sev", OWNER="root", GROUP="root", MODE="0600"' in out
+        assert 'KERNEL=="sev-guest", OWNER="root", GROUP="sevtest", MODE="0660"' in out
+
+        out = machine.succeed("cat /etc/group")
+        assert "sev:" not in out
+        assert "sev-guest:" not in out
+        assert "sevtest:" in out
+    '';
+}