nixosTests.incus: add ui test

nixos/tests/incus/default.nix

@@ -9,5 +9,6 @@
   lxd-to-incus = import ./lxd-to-incus.nix { inherit system pkgs; };
   preseed = import ./preseed.nix { inherit system pkgs; };
   socket-activated = import ./socket-activated.nix { inherit system pkgs; };
+  ui = import ./ui.nix {inherit system pkgs;};
   virtual-machine = handleTestOn [ "x86_64-linux" ] ./virtual-machine.nix { inherit system pkgs; };
 }

nixos/tests/incus/ui.nix

@@ -0,0 +1,63 @@
+import ../make-test-python.nix ({ pkgs, lib, ... }: {
+  name = "incus-ui";
+
+  meta = {
+    maintainers = lib.teams.lxc.members;
+  };
+
+  nodes.machine = { lib, ... }: {
+    virtualisation = {
+      incus.enable = true;
+      incus.ui.enable = true;
+    };
+
+    environment.systemPackages =
+      let
+        seleniumScript = pkgs.writers.writePython3Bin "selenium-script"
+          {
+            libraries = with pkgs.python3Packages; [ selenium ];
+          } ''
+          from selenium import webdriver
+          from selenium.webdriver.common.by import By
+          from selenium.webdriver.firefox.options import Options
+          from selenium.webdriver.support.ui import WebDriverWait
+
+          options = Options()
+          options.add_argument("--headless")
+          service = webdriver.FirefoxService(executable_path="${lib.getExe pkgs.geckodriver}")  # noqa: E501
+
+          driver = webdriver.Firefox(options=options, service=service)
+          driver.implicitly_wait(10)
+          driver.get("https://localhost:8443/ui")
+
+          wait = WebDriverWait(driver, 60)
+
+          assert len(driver.find_elements(By.CLASS_NAME, "l-application")) > 0
+          assert len(driver.find_elements(By.CLASS_NAME, "l-navigation__drawer")) > 0
+
+          driver.close()
+        '';
+      in
+      with pkgs; [ curl firefox-unwrapped geckodriver seleniumScript ];
+  };
+
+
+  testScript = ''
+    machine.wait_for_unit("sockets.target")
+    machine.wait_for_unit("incus.service")
+    machine.wait_for_file("/var/lib/incus/unix.socket")
+
+    # Configure incus listen address
+    machine.succeed("incus config set core.https_address :8443")
+    machine.succeed("systemctl restart incus")
+
+    # Check that the INCUS_UI environment variable is populated in the systemd unit
+    machine.succeed("cat /etc/systemd/system/incus.service | grep 'INCUS_UI'")
+
+    # Ensure the endpoint returns an HTML page with 'Incus UI' in the title
+    machine.succeed("curl -kLs https://localhost:8443/ui | grep '<title>Incus UI</title>'")
+
+    # Ensure the application is actually rendered by the Javascript
+    machine.succeed("PYTHONUNBUFFERED=1 selenium-script")
+  '';
+})