nixosTests.alloy: init VM test

This adds a VM test, starting up Grafana Alloy and ensuring it comes
up healthy.

nixos/tests/all-tests.nix

@@ -115,6 +115,7 @@ in {
   akkoma = handleTestOn [ "x86_64-linux" "aarch64-linux" ] ./akkoma.nix {};
   akkoma-confined = handleTestOn [ "x86_64-linux" "aarch64-linux" ] ./akkoma.nix { confined = true; };
   alice-lg = handleTest ./alice-lg.nix {};
+  alloy = handleTest ./alloy.nix {};
   allTerminfo = handleTest ./all-terminfo.nix {};
   alps = handleTest ./alps.nix {};
   amazon-init-shell = handleTest ./amazon-init-shell.nix {};

nixos/tests/alloy.nix

@@ -0,0 +1,32 @@
+import ./make-test-python.nix ({ lib, pkgs, ... }:
+
+  let
+    nodes = {
+      machine = {
+        services.alloy = {
+          enable = true;
+        };
+        environment.etc."alloy/config.alloy".text = "";
+      };
+    };
+  in
+  {
+    name = "alloy";
+
+    meta = with lib.maintainers; {
+      maintainers = [ flokli ];
+    };
+
+    inherit nodes;
+
+    testScript = ''
+      start_all()
+
+      machine.wait_for_unit("alloy.service")
+      machine.wait_for_open_port(12345)
+      machine.succeed(
+          "curl -sSfN http://127.0.0.1:12345/-/healthy"
+      )
+      machine.shutdown()
+    '';
+  })