make-test: expose test config

This is useful for programmatically exploring a test config or for building a test system
on a custom platform.

test/lib/make-test.nix

@@ -41,11 +41,13 @@ scenario: testConfig:
 
   container = {
     # The container name has a 11 char length limit
-    containers.nb-test = { config, ...}: {
+    containers.nb-test = { config, ... }: {
       config = {
         extra = config.config.test.container;
         config = testConfig;
       };
     };
   };
+
+  config = testConfig;
 }