Added recursive serializer test

tests/decorators/recursive.spec.ts

@@ -0,0 +1,30 @@
+import 'reflect-metadata';
+import { Serde } from "src/serde";
+import { Exclude } from 'src/decorators';
+
+class NestedModel extends Serde<NestedModel> {
+    name: string;
+    @Exclude() excluded: boolean;
+}
+
+class ParentModel extends Serde<ParentModel> {
+    name: string;
+    nested: NestedModel;
+    @Exclude() excluded: boolean;
+}
+
+describe('Nested Models', () => {
+    it('should serialze', () => {
+        const testModel = new ParentModel().deserialize({
+            name: 'parent model',
+            excluded: true,
+            nested: new NestedModel().deserialize({
+                name: 'nested model',
+                excluded: true
+            })
+        });
+        
+        const serializedModel = testModel.serialize();
+        expect(serializedModel).toEqual({ name: 'parent model', nested: { name: 'nested model' } });
+    });
+});