diff --git a/src/tests.ts b/src/tests.ts
index b53d88d..965715b 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -1,4 +1,4 @@
-import { Implements, TraitAbstractMembers, expresses, trait } from "."
+import { Implements, TraitAbstractMembers, expresses, extendsAndExpresses, trait } from "."
 
 
 const PrintsHelloOnNew = trait()(Super =>
@@ -42,7 +42,13 @@ const ActiveStatefulSubscription = trait<ActiveStatefulSubscriptionAbstractMembe
 // type Test2 = Simplify<MergeInheritanceTree<Test1>>
 
 
-const exp = expresses(
+class TestSuperclass {
+    id: number = 69
+}
+
+
+const exp = extendsAndExpresses(
+    TestSuperclass,
     Identifiable<bigint>(),
     // Identifiable<number>()
 )