wip: first PubSolarOS iso test using the NixOS

test suite:

https://nixos.org/manual/nixos/stable/index.html#sec-nixos-tests

flake.nix

@@ -122,7 +122,12 @@
           imports = [ (digga.lib.importHosts ./hosts) ];
           hosts = {
             /* set host specific properties here */
-            PubSolarOS = { };
+            PubSolarOS = {
+              tests = [
+                (import ./tests/first-test.nix {})
+                (import ./tests/second-test.nix {})
+              ];
+            };
             fae = {
               system = "aarch64-linux";
             };

tests/first-test.nix

@@ -0,0 +1,52 @@
+{ }:
+{
+  name = "firstTest";
+
+  nodes.test-machine = { suites ? null, ... }: {
+    imports = suites.iso;
+
+    environment = {
+      variables = {
+        "SWAYSOCK" = "/tmp/sway-ipc.sock";
+        # TODO: Investigate if we can get hardware acceleration to work (via
+        # virtio-gpu and Virgil). We currently have to use the Pixman software
+        # renderer since the GLES2 renderer doesn't work inside the VM (even
+        # with WLR_RENDERER_ALLOW_SOFTWARE):
+        # "WLR_RENDERER_ALLOW_SOFTWARE" = "1";
+        "WLR_RENDERER" = "pixman";
+      };
+
+      shellAliases = {
+        test-wayland = "wayland-info | tee /tmp/test-wayland.out && touch /tmp/test-wayland-exit-ok";
+      };
+    };
+
+    # Need to switch to a different GPU driver than the default one (-vga std) so that Sway can launch:
+    virtualisation.qemu.options = [ "-vga none -device virtio-gpu-pci" ];
+  };
+
+  enableOCR = true;
+
+  testScript = ''
+    machine.wait_for_unit("multi-user.target")
+    # To check the version:
+    print(machine.succeed("sway --version"))
+    # Wait for Sway to complete startup:
+    machine.wait_for_file("/run/user/1000/wayland-1")
+    machine.wait_for_file("/tmp/sway-ipc.sock")
+
+    # Start a terminal (alacritty) on workspace 3:
+    machine.send_key("super-3")
+    machine.sleep(3)
+    machine.send_key("super-ret")
+    machine.send_chars("whoami\n")
+    machine.wait_for_text("pub-solar")
+    machine.send_chars("test-wayland\n")
+    machine.wait_for_file("/tmp/test-wayland-exit-ok")
+    print(machine.succeed("cat /tmp/test-wayland.out"))
+    machine.copy_from_vm("/tmp/test-wayland.out")
+    machine.screenshot("alacritty_wayland_info")
+    machine.send_key("super-shift-q")
+    machine.wait_until_fails("pgrep alacritty")
+  '';
+}