diff --git a/crates/ailang-core/tests/workspace_pin.rs b/crates/ailang-core/tests/workspace_pin.rs
index cff7c62..5be74f6 100644
--- a/crates/ailang-core/tests/workspace_pin.rs
+++ b/crates/ailang-core/tests/workspace_pin.rs
@@ -49,9 +49,13 @@ fn loads_example_workspace_happy_path() {
     assert_eq!(ws.entry, "ws_main");
     assert!(ws.modules.contains_key("ws_main"));
     assert!(ws.modules.contains_key("ws_lib"));
-    // the loader auto-injects the `prelude` module,
-    // so the count is the user's two modules plus prelude.
-    assert_eq!(ws.modules.len(), 3);
+    // the loader auto-injects two built-in kernel-tier modules
+    // (`prelude` and `kernel_stub` — see prep.3 of the
+    // kernel-extension-mechanics milestone), so the count is the
+    // user's two modules plus those two.
+    assert_eq!(ws.modules.len(), 4);
+    assert!(ws.modules.contains_key("prelude"));
+    assert!(ws.modules.contains_key("kernel_stub"));
 }
 
 #[test]