nixos/tests/caddy: add pkgs.caddy.withPlugins test

nixos/tests/caddy.nix

@@ -3,12 +3,15 @@ import ./make-test-python.nix (
   {
     name = "caddy";
     meta = with pkgs.lib.maintainers; {
-      maintainers = [ Br1ght0ne ];
+      maintainers = [
+        Br1ght0ne
+        stepbrobd
+      ];
     };
 
     nodes = {
       webserver =
-        { pkgs, lib, ... }:
+        { pkgs, ... }:
         {
           services.caddy.enable = true;
           services.caddy.extraConfig = ''
@@ -63,6 +66,24 @@ import ./make-test-python.nix (
               respond "hello world"
             '';
           };
+          specialisation.with-plugins.configuration = {
+            services.caddy = {
+              package = pkgs.caddy.withPlugins {
+                plugins = [ "github.com/caddyserver/[email protected]" ];
+                hash = "sha256-zgMdtOJbmtRSfTlrrg8njr11in2C7OAXLB+34V23jek=";
+              };
+              configFile = pkgs.writeText "Caddyfile" ''
+                {
+                  order replace after encode
+                }
+
+                localhost:80 {
+                  respond "hello world"
+                  replace world caddy
+                }
+              '';
+            };
+          };
         };
     };
 
@@ -73,6 +94,7 @@ import ./make-test-python.nix (
         justReloadSystem = "${nodes.webserver.system.build.toplevel}/specialisation/config-reload";
         multipleConfigs = "${nodes.webserver.system.build.toplevel}/specialisation/multiple-configs";
         rfc42Config = "${nodes.webserver.system.build.toplevel}/specialisation/rfc42";
+        withPluginsConfig = "${nodes.webserver.system.build.toplevel}/specialisation/with-plugins";
       in
       ''
         url = "http://localhost/example.html"
@@ -108,6 +130,13 @@ import ./make-test-python.nix (
             )
             webserver.wait_for_open_port(80)
             webserver.succeed("curl http://localhost | grep hello")
+
+        with subtest("plugins are correctled installed and configurable"):
+            webserver.succeed(
+                "${withPluginsConfig}/bin/switch-to-configuration test >&2"
+            )
+            webserver.wait_for_open_port(80)
+            webserver.succeed("curl http://localhost | grep caddy")
       '';
   }
 )