diff --git a/src/tests.ts b/src/tests.ts
index 3eddcd5..39ad805 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -1,17 +1,19 @@
 import { z } from "zod"
 import { makeSchemableClass, newSchemable } from "."
-import { dejsonifyBigIntSchema, jsonifyBigIntSchema, makeJsonifiableSchemableClass } from "./jsonifiable"
+import { dejsonifyBigIntSchema, dejsonifySchemableSchema, jsonifyBigIntSchema, jsonifySchemableSchema, makeJsonifiableSchemableClass } from "./jsonifiable"
 
 
-const UserSchema = z.object({
-    /** User ID */
-    id: z.bigint().default(-1n)
+const GroupSchema = z.object({
+    /** Group ID */
+    id: z.bigint(),
+
+    /** Group name */
+    name: z.string(),
 })
 
+const GroupSchemableObject = makeSchemableClass({ schema: GroupSchema })
 
-const UserSchemableObject = makeSchemableClass({ schema: UserSchema })
-
-const UserJsonifiableSchemableObject = makeJsonifiableSchemableClass(UserSchemableObject, {
+const GroupJsonifiableSchemableObject = makeJsonifiableSchemableClass(GroupSchemableObject, {
     jsonifySchema: ({ schema, s }) => schema.extend({
         id: jsonifyBigIntSchema(s.id)
     }),
@@ -21,12 +23,40 @@ const UserJsonifiableSchemableObject = makeJsonifiableSchemableClass(UserSchemab
     }),
 })
 
+class Group extends GroupJsonifiableSchemableObject {}
+
+
+const UserSchema = z.object({
+    /** User ID */
+    id: z.bigint(),
+
+    /** Name string */
+    name: z.string(),
+
+    /** User group */
+    group: z.instanceof(Group),
+})
+
+const UserSchemableObject = makeSchemableClass({ schema: UserSchema })
+
+const UserJsonifiableSchemableObject = makeJsonifiableSchemableClass(UserSchemableObject, {
+    jsonifySchema: ({ schema, s }) => schema.extend({
+        id: jsonifyBigIntSchema(s.id),
+        group: jsonifySchemableSchema(Group, s.group),
+    }),
+
+    dejsonifySchema: ({ schema, s }) => schema.extend({
+        id: dejsonifyBigIntSchema(s.id),
+        group: dejsonifySchemableSchema(Group, s.group),
+    }),
+})
+
 class User extends UserJsonifiableSchemableObject {}
 
-const user1 = new User({ id: 1n })
-const user2 = newSchemable(User, { id: 2n })
 
-console.log(user1)
-console.log(user2)
+const group1 = new Group({ id: 1n, name: "Group 1" })
 
-console.log(await user2.jsonifyPromise())
+const user1 = new User({ id: 1n, name: "User 1", group: group1 })
+const user2 = newSchemable(User, { id: 2n, name: "User 2", group: group1 })
+
+console.log(user2.jsonify())