ci: type-check the semi-spread and swarm-builder-offline test scripts with stand-in values

nix/vm-test-typecheck.nix

@@ -54,13 +54,18 @@ let
     echo -n "$testScript" >> testScriptWithTypes
   '';
 
+  # The tests that interpolate node config or an agent toplevel name a stand-in
+  # script in `passthru.typecheckScript`, built by the same function as their real
+  # `testScript`; reading `testScriptString` there would evaluate a NixOS system.
+  scriptOf = test: test.config.passthru.typecheckScript or test.config.testScriptString;
+
   typecheck =
     name: test:
     pkgs.runCommand "vm-test-typecheck-${name}"
       (
         checkInputs
         // {
-          testScript = test.config.testScriptString;
+          testScript = scriptOf test;
           hints = hintsFor test;
         }
       )
@@ -120,10 +125,6 @@ let
         touch $out
       '';
 
-  # semi-spread and swarm-builder-offline are not listed: they interpolate node
-  # config or an agent toplevel into their script, so reading the script text
-  # evaluates a NixOS system. They need their script to be a function of those
-  # values first.
   tests = {
     inherit (vmTests)
       hive-squid
@@ -131,6 +132,8 @@ let
       agent-ephemeral-rootfs
       full-setup
       wg-hive
+      semi-spread
+      swarm-builder-offline
       ;
   };
 in