too lazy to think of a message, so enjoy this pointless text. Good luck future me...

checks/customer-portal/default.nix

@@ -0,0 +1,22 @@
+{
+  pkgs,
+  nixosLib,
+  clan-core,
+  ...
+}:
+nixosLib.runTest (
+  { ... }:
+  {
+    imports = [
+      clan-core.modules.nixosTest.clanTest
+    ];
+
+    hostPkgs = pkgs;
+
+    name = "service-customer-portal";
+
+    testScript = ''
+      start_all()
+    '';
+  }
+)

checks/flake-module.nix

@@ -0,0 +1,15 @@
+{ self, ... }:
+let
+  nixosLib = import (self.inputs.nixpkgs + "/nixos/lib") { };
+in
+{
+  perSystem = { pkgs, lib, ... }:
+  {
+    checks = {
+      service-customer-portal-test = import ./customer-portal {
+        inherit pkgs lib nixosLib self;
+        inherit (self.inputs) clan-core;
+      };
+    };
+  };
+}