diff --git a/src/tests.ts b/src/tests.ts
index ce37480..b76de19 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -1,6 +1,6 @@
 import { pipeInto } from "ts-functional-pipe"
 import { z } from "zod"
-import { makeSchemableClass, newSchemable } from "."
+import { extendSchemableClass, makeSchemableClass, newSchemable } from "."
 import { makeJsonifiableSchemableClass } from "./jsonifiable"
 import { dejsonifyBigIntSchema, jsonifyBigIntSchema } from "./legacy/jsonifiable"
 
@@ -49,4 +49,22 @@ class User extends pipeInto(
 
 
 const user1 = newSchemable(User, { id: 1n, name: "User" })
-user1.jsonify()
+console.log(user1.jsonify())
+
+
+const UserWithPhone = extendSchemableClass(User, {
+    schema: schema => schema.extend({
+        phone: z.string()
+    }),
+
+    defaultValues: defaultValues => ({
+        ...defaultValues,
+        phone: "+33600000000",
+    }),
+})
+
+UserWithPhone.schema
+
+
+const user2 = newSchemable(UserWithPhone, { id: 1n, name: "User" })
+console.log(user2.jsonify())